Iris Script

Script Language Reference Edition: 2013

Script Language Reference

Iris, Greek goddess of the rainbow

Software that brings information

The choice to name our software Iris is well thought over. You will find remarkable unique

features that very well compare to how the Greek goddess Iris is described.

In Greek mythology, Iris is a goddess of communication. She is the messenger of the gods, particularly Zeus and Hera, to humankind. She is pictured with wings and personifies the rainbow. It was said that Iris leaves Mount Olympus only to deliver messages to mankind who look to her as an advisor and guide, linking her between the worlds of the gods and humanity.

One of the strong features of Iris SCADA and PanelWare relates to communication with the process. No other SCADA or PanelWare software supports the same high and accurate

performance to bring process and production data to the operators, and back.

Apart from carrying messages Goddess Iris had many other tasks to perform. One was to deliver a jug of water from the river Styx so to put whoever lies to sleep. The Greek called her 'The source of water from above'. If the Gods argue, or if they lie about something, Iris will get water out of the river Styx. With this water, the Gods must pledge the truth. If they lied, they lost their immortality.

Besides the strong communication in Iris SCADA and PanelWare you also will find many smart engineering tools that will help you to generate quickly solutions for different type of

applications. Iris SCADA and PanelWare holds a very strong event driven task handler. This guarantees that data is always handled correctly and communicated to the different modules

(e.g. alarming, trending, visualization and more).

Travelling through all dimensions, Iris uses her gifts to prevent unnecessary suffering by severing the silver cord that binds them to Mother Earth bringing relief from a slow death. Though she was sometimes called upon to deliver bad news, Iris was known as a sweet tempered Goddess with no enemies. This gave her access to the universe and welcome in all corners of the earth and beyond.

Iris SCADA and PanelWare is independent from whatever type of control equipment. The unique architecture is suited for a wide variety of applications. Iris SCADA and PanelWare can

be used in small stations and in large control rooms, in simple to mission critical applications. Iris SCADA and PanelWare can be fully adjusted and new functionality can be added always.

Iris not being a mere follower and deliverer of others' messages, her other qualities are gentle strength and communication skills born out of the art of balance. She arrests action and creates harmony. Iris is a bringer of hope and justice through temperance rather than force. It has been said that all the colours of the rainbow blended together create the colour white, essence of the Spirit.

Iris SCADA and PanelWare is not comparable with regular SCADA systems. It is software

developed by engineers for engineers allowing easy and rapid application development, saving valuable engineering time. Even changes to the application can be made without

stopping the process, if needed from a remote development station. All the different modules in Iris SCADA and PanelWare make it an ideal platform to develop specific solutions.


Abstract This document is the Script Language Reference for Iris, a product of Raster Products B.V. Iris is a program build to control and visualize data from Programmable logic Controllers

(PLC) or Process Control Systems (PCS) through highly efficient data communication. Iris is

equipped with lots of extensive features, provided to create the best possible interface with the user.

Raster Products B.V.

P.O. box 3

6620 AA DREUMEL

The Netherlands

Phone: +31 (0)487-572719

Fax: +31 (0)487-573394

E-mail: [email protected]

Website: www.raster.com


History

Edition Date Author Description

2009 16-JUL-2009 Alex Oskam Newly written for Iris V4

2011 28-JAN-2011 Alex Oskam Slightly updated

2013 10-AUG-2013 RvW Slightly updated

This document is property of Raster Products B.V. No part of it may be reproduced or used in

any form or by any means without written permission of the owner.

Although this manual is written with the most care, Raster will not be responsible for any mistakes in this manual or damage that is a result of the information in this manual.


Table of Contents 1. Abort - Aborts the current processing with a silent exception ...................................... 12

2. Abs - Gives the absolute value of a number (-ve sign is removed) .............................. 13

3. And - Boolean and or bitwise and of two arguments .................................................. 14

4. AnsiChar - A character type guaranteed to be 8 bits in size ........................................ 15

5. AnsiCompareStr - Compare two strings for equality .................................................... 16

6. AnsiCompareText - Compare two strings for equality, ignoring case ............................ 18

7. AnsiLowerCase - Change upper case characters in a string to lower case .................... 20

8. AnsiPos - Find the position of one string in another .................................................... 21

9. AnsiString - A data type that holds a string of AnsiChars ............................................ 22

10. AnsiUpperCase - Change lower case characters in a string to upper case .................. 24

11. Append - Open a text file to allow appending of text to the end ............................... 25

12. ArcCos - The Arc Cosine of a number, returned in radians ........................................ 27

13. ArcSin - The Arc Sine of a number, returned in radians ............................................ 28

14. ArcTan - The Arc Tangent of a number, returned in radians ..................................... 29

15. Array - A data type holding indexable collections of data .......................................... 30

16. AssignFile - Assigns a file handle to a binary or text file ........................................... 32

17. Beep - Make a beep sound ..................................................................................... 34

18. Begin - Keyword that starts a statement block ......................................................... 35

19. Boolean - Allows just True and False values ............................................................ 36

20. Break - Forces a jump out of a single loop .............................................................. 37

21. Byte - An integer type supporting values 0 to 255 ................................................... 38

22. Cardinal - The basic unsigned integer type .............................................................. 39

23. Case - A mechanism for acting upon different values of an Ordinal ........................... 40

24. ChangeFileExt - Change the extension part of a file name ........................................ 42

25. ChangePage - Change a page ................................................................................ 43

26. Char - Variable type holding a single character ........................................................ 44

27. ChDir - Change the working drive plus path for a specified drive .............................. 45

28. Chr - Convert an integer into a character ................................................................ 46

29. ClearMailBox - Clears the current MailBox................................................................ 47

30. CloseCurrentPage - Close a screen .......................................................................... 48

31. CloseFile - Closes an open file ................................................................................ 49

32. CompareStr - Compare two strings for equality ....................................................... 51

33. CompareText - Compare two strings for equality, ignoring case ................................ 53

34. CompareValue - Compare numeric values with a tolerance ....................................... 55

35. Const - Starts the definition of fixed data values ...................................................... 57

36. Continue - Forces a jump to the next iteration of a loop ........................................... 58

37. Copy - Create a copy of part of a string or an array ................................................. 59

38. Cos - The Cosine of a number ................................................................................ 60

39. CreateDir - Create a directory ................................................................................. 61

40. Currency - A floating point type with 4 decimals used for financial values ................. 62

41. CurrencyDecimals - Defines decimal digit count in the Format function ..................... 63

42. CurrencyFormat - Defines currency string placement in curr display functions ........... 64


43. CurrencyString - The currency string used in currency display functions .................... 65

44. CurrentPageName - Show the current page name ................................................... 66

45. CurrToStr - Convert a currency value to a string ...................................................... 67

46. CurrToStrF - Convert a currency value to a string with formatting............................. 68

47. Date - Gives the current date ................................................................................. 69

48. DateSeparator - The character used to separate display date fields .......................... 70

49. DateTimeToFileDate - Convert a TDateTime value to a file date/time format ............. 71

50. DateTimeToStr - Converts TDateTime date and time values to a string ..................... 73

51. DateTimeToString - Rich formatting of a TDateTime variable into a string ................. 74

52. DateToStr - Converts a TDateTime date value to a string ......................................... 77

53. DayOfTheMonth - Gives day of month index for a TDateTime value (ISO 8601) ........ 78

54. DayOfTheWeek - Gives day of week index for a TDateTime value (ISO 8601) ........... 79

55. DayOfTheYear - Gives the day of the year for a TDateTime value (ISO 8601) ........... 80

56. DayOfWeek - Gives day of week index for a TDateTime value .................................. 81

57. DaysBetween - Gives the whole number of days between 2 dates ............................ 82

58. DaysInAMonth - Gives the number of days in a month ............................................. 83

59. DaysInAYear - Gives the number of days in a year .................................................. 84

60. DaySpan - Gives the fractional number of days between 2 dates .............................. 85

61. Dec - Decrement an ordinal variable ....................................................................... 86

62. DecimalSeparator - The character used to display the decimal point ......................... 87

63. DecodeDate - Extracts the year, month, day values from a TDateTime var. .............. 88

64. DecodeTime - Break a TDateTime value into individual time values .......................... 89

65. DegToRad - Convert a degrees value to radians ...................................................... 90

66. Delete - Delete a section of characters from a string ................................................ 91

67. DeleteFile - Delete a file specified by its file name ................................................... 92

68. DirectoryExists - Returns true if the given directory exists ........................................ 94

69. Div - Performs integer division, discarding the remainder ......................................... 95

70. Do - Defines the start of some controlled action ...................................................... 96

71. Double - A floating point type supporting about 15 digits of precision ....................... 97

72. Downto - Prefixes an decremental for loop target value ........................................... 98

73. Else - Starts false section of if, case and try statements ........................................... 99

74. EncodeDate - Build a TDateTime value from year, month and day values ............... 101

75. EncodeDateTime - Build a TDateTime value from day and time values .................... 102

76. EncodeTime - Build a TDateTime value from hour, min, sec and msec values.......... 103

77. End - Keyword that terminates statement blocks ................................................... 104

78. EndOfADay - Generate a TDateTime value set to the very end of a day .................. 105

79. EndOfAMonth - Generate a TDateTime value set to the very end of a month .......... 106

80. Eof - Returns true if a file opened with Reset is at the end ..................................... 107

81. Erase - Erase a file............................................................................................... 109

82. Except - Starts the error trapping clause of a try statement .................................... 110

83. Exit - exit abruptly from a function or procedure .................................................... 111

84. Exp - Gives the exponent of a number .................................................................. 112

85. ExpandMailBox - Expands a MailBox ..................................................................... 113

86. ExpandPowerTree - Expands a PowerTree ............................................................ 114


87. ExtractFileDir - Extracts the dir part of a full file name ........................................... 115

88. ExtractFileDrive - Extracts the drive part of a full file name .................................... 116

89. ExtractFileExt - Extracts the extension part of a full file name ................................. 117

90. ExtractFileName - Extracts the name part of a full file name ................................... 118

91. ExtractFilePath - Extracts the path part of a full file name ...................................... 119

92. File - Defines a typed or untyped file .................................................................... 120

93. FileAge - Get the last modified date/time of a file without opening it ...................... 122

94. FileDateToDateTime - Converts a file date/time format to a TDateTime value ......... 123

95. FileExists - Returns true if the given file exists ....................................................... 124

96. FileGetAttr - Gets the attributes of a file ................................................................ 126

97. FileSearch - Search for a file in one or more directories .......................................... 129

98. FileSetDate - set the last modified date and time of a file ....................................... 131

99. Finally - Starts the unconditional code section of a try statement ............................ 133

100. FloatToStr - Convert a floating point value to a string .......................................... 135

101. FloatToStrF - Convert a floating point value to a string with formatting ................ 136

102. Flush - Flushes buffered text file data to the file .................................................. 139

103. For - Starts a loop that executes a finite number of times .................................... 141

104. ForceDirectories - Create a new path of directories ............................................. 142

105. Format - Rich formatting of numbers and text into a string .................................. 143

106. FormatCurr - Rich formatting of a currency value into a string ............................. 146

107. FormatDateTime - Rich formatting of a TDateTime variable into a string .............. 149

108. FormatFloat - Rich formatting of a floating point number into a string .................. 154

109. Frac - The fractional part of a floating point number ............................................ 157

110. Function - Defines a subroutine that returns a value ............................................ 158

111. GetCurrentDir - Get the current directory (drive plus directory) ............................ 161

112. GetDir - Get the default directory (drive plus path) for a specified drive ................ 162

113. GetPageDir - Returns the page directory ............................................................. 163

114. GetTagProp - Reads a property of a tag.............................................................. 164

115. GetTagValue - Reads the value of a tag .............................................................. 166

116. Goto - Forces a jump to a label, regardless of nesting ......................................... 169

117. If - Starts a conditional expression to determine what to do next ......................... 170

118. Implementation - Starts the implementation (code) section of a unit .................... 172

119. Inc - Increment an ordinal variable .................................................................... 175

120. IncDay - Increments a TDateTime variable by + or - number of days ................... 176

121. IncMillisecond - Increments a TDateTime variable by + or - number of mseconds . 177

122. IncMinute - Increments a TDateTime variable by + or - number of minutes .......... 178

123. IncMonth - Increments a TDateTime variable by a number of months .................. 179

124. IncSecond - Increments a TDateTime variable by + or - number of seconds ......... 180

125. IncYear - Increments a TDateTime variable by a number of years ........................ 181

126. Infinity - Floating point value of infinite size ........................................................ 182

127. InputBox - Display a dialog that asks for user text input, with default ................... 183

128. InputQuery - Display a dialog that asks for user text input ................................... 184

129. Insert - Insert a string into another string ........................................................... 185

130. Int - The integer part of a floating point number as a float .................................. 186


131. Integer - The basic Integer type ........................................................................ 187

132. Interface - Used for definitions ........................................................................... 188

133. IntToHex - Convert an Integer into a hexadecimal string ..................................... 191

134. IntToStr - Convert an integer into a string .......................................................... 192

135. IsInfinite - Checks whether a floating point number is infinite .............................. 193

136. IsLeapYear - Returns true if a given calendar year is a leap year .......................... 194

137. LastDelimiter - Find the last position of selected characters in a string .................. 195

138. Length - Return the number of elements in an array or string .............................. 196

139. LinkedPopup - Open a Linked Popup .................................................................. 197

140. Ln - Gives the natural logarithm of a number ...................................................... 198

141. Log10 - Gives the log to base 10 of a number ..................................................... 199

142. LongDateFormat - Long version of the date to string format ................................ 200

143. LongInt - An Integer whose size is guaranteed to be 32 bits ................................ 201

144. LongTimeFormat - Long version of the time to string format ................................ 202

145. LowerCase - Change upper case characters in a string to lower case .................... 203

146. Max - Gives the maximum of two integer values ................................................. 204

147. MessageBox - Displays a message, symbol, and selectable buttons ...................... 205

148. MessageDlg - Displays a message, symbol, and selectable buttons ....................... 206

149. MessageDlgPos - Displays a message plus buttons at a given screen position ....... 208

150. Min - Gives the minimum of two integer values ................................................... 210

151. MinsPerDay - Gives the number of minutes in a day ............................................ 211

152. MkDir - Make a directory .................................................................................... 212

153. Mod - Performs integer division, returning the remainder..................................... 213

154. ModalPopup - Open a Modal Popup .................................................................... 214

155. MonthOfTheYear - Gives the month of the year for a TDateTime value ................. 215

156. NegCurrFormat - Defines negative amount formatting in currency displays ........... 216

157. Not - Boolean not or bitwise not of one arguments .............................................. 218

158. Now - Gives the current date and time ............................................................... 219

159. Null - A variable that has no value ...................................................................... 220

160. NumEditor - Shows a numerical popup to write the value of a tag ........................ 222

161. Or - Boolean or or bitwise or of two arguments ................................................... 224

162. Ord - Provides the Ordinal value of an integer, character or enum........................ 225

163. PageBack - Show Previous Page ......................................................................... 227

164. PageForward - Show Next Page ......................................................................... 228

165. Pi - The mathematical constant .......................................................................... 229

166. Popup - Open a Popup ...................................................................................... 230

167. Pos - Find the position of one string in another ................................................... 231

168. Pred - Decrement an ordinal variable .................................................................. 232

169. Private - Starts the section of private data and methods in a class ....................... 233

170. Procedure - Defines a subroutine that does not return a value ............................. 234

171. PtInRect - Tests to see if a point lies within a rectangle ....................................... 237

172. Public - Starts an externally accessible section of a class...................................... 238

173. RadToDeg - Converts a radian value to degrees .................................................. 239

174. Random - Generate a random floating point or integer number ............................ 240


175. Randomize - Reposition the Random number generator next value ...................... 242

176. RandomRange - Generate a random integer number within a supplied range........ 244

177. RandSeed - Reposition the Random number generator next value ........................ 245

178. ReadLn - read a complete line of data from a text file ......................................... 247

179. ReadRecipe - read a recipe file. .......................................................................... 249

180. RecodeDate - Change only the date part of a TDateTime variable ........................ 250

181. RecodeTime - Change only the time part of a TDateTime variable ........................ 251

182. RemoveDir - Remove a directory ........................................................................ 252

183. RemoveMailBox - Removes a MailBox ................................................................. 253

184. Rename - Rename a file .................................................................................... 254

185. Repeat - repeat statements until a ternmination condition is met ......................... 256

186. ReplaceDate - Change only the date part of a TDateTime variable ....................... 258

187. ReplaceTime - Change only the time part of a TDateTime variable ....................... 259

188. Result - A variable used to hold the return value from a function ......................... 260

189. ReWrite - Open a text or binary file for write access ............................................ 261

190. RmDir - Remove a directory ............................................................................... 263

191. Round - Rounds a floating point number to an integer ......................................... 264

192. SecsPerDay - Gives the number of seconds in a day ............................................ 265

193. SetCurrentDir - Change the current directory ...................................................... 266

194. SetMailBox - Sets a MailBox to a specific value .................................................... 267

195. SetPageDir - Sets the page directory .................................................................. 268

196. SetTagValue - Sets a value of a tag .................................................................... 269

197. Shl - Shift an integer value left by a number of bits ............................................. 272

198. ShortDateFormat - Compact version of the date to string format .......................... 273

199. ShortInt - An integer type supporting values -128 to 127 ..................................... 274

200. ShortString - Defines a string of up to 255 characters .......................................... 275

201. ShortTimeFormat - Short version of the time to string format .............................. 276

202. ShowMessage - Display a string in a simple dialog with an OK button ................... 277

203. ShowMessageFmt - Display formatted data in a simple dialog with an OK button .. 278

204. ShowMessagePos - Display a string in a simple dialog at a given screen position ... 281

205. Shr - Shift an integer value right by a number of bits .......................................... 282

206. Sin - The Sine of a number ................................................................................ 283

207. Single - The smallest capacity and precision floating point type ............................ 284

208. SmallInt - An Integer type supporting values from -32768 to 32767 ..................... 285

209. Sqr - Gives the square of a number .................................................................... 286

210. Sqrt - Gives the square root of a number ............................................................ 287

211. StopRunTime - Stops the runtime....................................................................... 288

212. String - A data type that holds a string of characters ........................................... 289

213. StringReplace - Replace one or more substrings found within a string .................. 290

214. StrToCurr - Convert a number string into a currency value ................................... 291

215. StrToDate - Converts a date string into a TDateTime value .................................. 293

216. StrToDateTime - Converts a date+time string into a TDateTime value .................. 294

217. StrToFloat - Convert a number string into a floating point value ........................... 295

218. StrToInt - Convert an integer string into an Integer value .................................... 296


219. StrToIntDef - Convert a string into an Integer value with default ......................... 298

220. StrToTime - Converts a time string into a TDateTime value ................................. 300

221. Succ - Increment an ordinal variable .................................................................. 301

222. Tan - The Tangent of a number ......................................................................... 302

223. TBits - An object that can hold an infinite number of Boolean values .................... 303

224. TDateTime - Data type holding a date and time value ......................................... 305

225. TextFile - Declares a file type for storing lines of text .......................................... 306

226. TFloatFormat - Formats for use in floating point number display functions ............ 308

227. TFormatSettings - A record for holding locale values ........................................... 311

228. Then - Part of an if statement - starts the true clause.......................................... 313

229. ThousandSeparator - The character used to display the thousands separator ........ 315

230. Time - Gives the current time ............................................................................ 316

231. TimeAMString - Determines AM value in DateTimeToString procedure .................. 317

232. TimePMString - Determines PM value in DateTimeToString procedure .................. 318

233. TimeSeparator - The character used to separate display time fields ...................... 319

234. TimeToStr - Converts a TDateTime time value to a string .................................... 320

235. To - Prefixes an incremental for loop target value ............................................... 321

236. Tomorrow - Gives the date tomorrow ................................................................. 322

237. Trim - Removes leading and trailing blanks from a string ..................................... 323

238. TrimLeft - Removes leading blanks from a string ................................................. 324

239. TrimRight - Removes trailing blanks from a string ............................................... 325

240. Trunc - The integer part of a floating point number ............................................. 326

241. Try - Starts code that has error trapping ............................................................. 327

242. TStringList - Holds a variable length list of strings ............................................... 330

243. TwoDigitYearCenturyWindow - Sets the century threshold for 2 digit years ........... 334

244. Unit - Defines the start of a script file ................................................................. 335

245. Until - Ends a repeat control loop ....................................................................... 338

246. UpperCase - Change lower case characters in a string to upper case .................... 340

247. Uses - Declares a list of Units to be imported ...................................................... 341

248. Var - Starts the definition of a section of data variables ....................................... 344

249. Variant - A variable type that can hold changing data types ................................. 346

250. VarType - Gives the current type of a Variant variable ......................................... 347

251. VarTypeMask - Mask for the meta-type part of a Variant variable ......................... 350

252. While - repeat statements whilst a continuation condition is met .......................... 353

253. WideString - A data type that holds a string of WideChars ................................... 355

254. Word - An integer type supporting values 0 to 65535 .......................................... 357

255. WriteLn - write a complete line of data to a text file ............................................ 358

256. WriteRecipe - write a recipe file.......................................................................... 360

257. WriteTagValue - Writes a value of a tag .............................................................. 361

258. Xor - Boolean xor or bitwise xor of two arguments .............................................. 364

259. Yesterday - Gives the date yesterday.................................................................. 365


Error! Use the Home tab to apply Kop 1 to the text that you want to appear here.Error! Use the Home tab to apply Kop 1

to the text that you want to appear here.

Page 12 of 366

1. Abort - Aborts the current processing with a silent exception

1.1. Unit

SysUtils

1.2. Type

Procedure

1.3. Description

The Abort procedure stops the current processing and exits to the last exception block. In

doing so, no end user message is produced - the abort is silent.

1.4. Syntax procedure Abort;

1.5. Example

1.5.1. Name

Aborting from a try block

1.5.2. Code begin

// enter a try block

try

ShowMessage('Before abort');

Abort;

ShowMessage('After abort');

except

ShowMessage('Exception occurred');

end;

ShowMessage('After try');

end;

1.5.3. Result Before abort

Exception occurred

After try




Page 13 of 366

2. Abs - Gives the absolute value of a number (-ve sign is removed)

2.1. Unit

System

2.2. Type

Function

2.3. Description

The Abs function returns the absolute value of a negative or positive number. It does this by

removing a negative sign, if found. The Number can be any numeric type, and can even be a Variant, as long as it can be converted to a number. For example, a Variant set to a string '-

1.23' will work fine. Always, Abs converts the Variant to an Extended floating point number

prior to removing any negative sign, even if the result is an integer value.

2.4. Syntax function Abs(Number : Numeric type) : Numeric type;

2.5. Example

2.5.1. Name

Illustrating absolute values of different data types

2.5.2. Code var

float : single;

int : Integer;

varVar : Variant;

begin

float := -1.5; // small negative floating point number

int := -7; // negative integer

varVar := '-98'; // variants are converted to floating point!

ShowMessage('Abs(float) = '+FloatToStr(Abs(float)));

ShowMessage('Abs(int) = '+FloatToStr(Abs(int)));

// variants are converted into extended floating types

float := Abs(varVar);

ShowMessage('Abs(varVar) = '+FloatToStr(float));

end;

2.5.3. Result Abs(float) = 1.5

Abs(int) = 7

Abs(varVar) = 98




Page 14 of 366

3. And - Boolean and or bitwise and of two arguments

3.1. Unit

Iris Standard

3.2. Type

Keyword

3.3. Description

The and keyword is used in two different ways: 1. to perform a logical or Boolean 'and' of

two logical values. If both are true, then the result is true, otherwise, the result is false. 2. To

perform a mathematical 'and' of two integers. The result is a bitwise 'and' of the two numbers. For example: 10110001 and 01100110 = 00100000

3.4. Syntax 1 Boolean expression and Boolean expression

2 Integer expression and Integer expression

3.5. Example

3.5.1. Name

Illustrate both types of and usage

3.5.2. Code var

num1, num2, num3 : Integer;

letter : Char;

begin

num1 := $25; // binary value : 0010 0101

num2 := $32; // binary value : 0011 0010

// and-ed value : 0010 0000 = $20 = 32 dec

letter := 'G';

// and used to return a boolean value

if (num1 > 0) and (letter = 'G')

then ShowMessage('Both values are true')

else ShowMessage('None or only one true value');

// and used to perform a mathematical and operation

num3 := num1 and num2;

ShowMessageFmt('$25 and $32 = $%x',[num3]);

end;

3.5.3. Result Both values are true

$25 and $32 = $20




Page 15 of 366

4. AnsiChar - A character type guaranteed to be 8 bits in size

4.1. Unit

System

4.2. Type

Type

4.3. Description

The AnsiChar type is used to hold single characters. It is guaranteed to be 8 bits in size. It

can be assigned from a character or integer value.

4.4. Syntax type AnsiChar = #0..#255;

4.5. Example

4.5.1. Name

Different ways of assigning to and from an AnsiChar

4.5.2. Code var

myChar : AnsiChar;

begin

myChar := 'g'; // assign from a character constant

ShowMessage('Letter g = '+myChar);

myChar := #65; // assign from an integer constant

ShowMessage('#65 = '+myChar);

myChar := Chr(66); // using chr to convert a number

ShowMessage('Chr(66) = '+myChar);

end;

4.5.3. Result Letter g = g

#65 = A

Chr(66) = B




Page 16 of 366

5. AnsiCompareStr - Compare two strings for equality

5.1. Unit

SysUtils

5.2. Type

Function

5.3. Description

The AnsiCompareStr function compares String1 and String2 for equality. This is the modern,

Locale safe form of CompareStr. All Ansi commands support multi-byte and accented

characters. It returns these values: String1 < String2 : -ve numberString1 = String2 : 0String1 > String2 : +ve number The comparison is not affected by length - it is carried out

on a letter by letter basis. But a longer string is greater than a shorter, otherwise matching string. The comparison is case sensitive.

5.4. Syntax function AnsiCompareStr(const String1, String2 : string) : Integer;




Page 17 of 366

5.5. Example

5.5.1. Name

Compare various strings

5.5.2. Code // remember to declare the procedure at type using the following line

// procedure comparestrings(const string1, string2: string);

begin

// compare two obviously different strings

CompareStrings('HELLO', 'WORLD');

// compare identical strings

CompareStrings('Hi 2 you', 'Hi 2 you');

// upper case letters follow lower case in iris

CompareStrings('ABC', 'abc');

// all letters follow numbers in iris

CompareStrings('abc', '123');

end;

// compare two strings, and show which is bigger than the other

procedure TUntitled.CompareStrings(const string1, string2: string);

var

result : Integer;

begin

// compare some strings

result := AnsiCompareStr(string1, string2);

if result < 0 then ShowMessage(string1+' < '+string2);

if result = 0 then ShowMessage(string1+' = '+string2);

if result > 0 then ShowMessage(string1+' > '+string2);

end;

5.5.3. Result HELLO < WORLD

Hi 2 you = Hi 2 you

ABC > abc

abc > 123




Page 18 of 366

6. AnsiCompareText - Compare two strings for equality, ignoring case

6.1. Unit

SysUtils

6.2. Type

Function

6.3. Description

The AnsiCompareText function compares String1 and String2 for equality, ignoring case. This

is the modern, Locale safe form of CompareStr. All Ansi commands support multi-byte and accented characters. It returns these values: String1 < String2 : -ve numberString1 = String2

: 0String1 > String2 : +ve number The comparison is not affected by length - it is carried out

on a letter by letter basis. But a longer string is greater than a shorter, otherwise matching string.

6.4. Syntax function AnsiCompareText(const String1, String2 : string) : Integer;




Page 19 of 366

6.5. Example

6.5.1. Name




begin





// ansicomparetext treats upper and lower case identically

CompareStrings('ABCdef', 'abcDEF');



end;



var

result : Integer;

begin


result := AnsiCompareText(string1, string2);




end;


Hi 2 you = Hi 2 you

ABCdef = abcDEF

abc > 123




Page 20 of 366

7. AnsiLowerCase - Change upper case characters in a string to lower case

7.1. Unit

SysUtils

7.2. Type

Function

7.3. Description

The AnsiLowerCase function creates a copy of MixedString with all letters converted to lower

case. All Ansi commands support multi-byte and accented characters.

7.4. Syntax function AnsiLowerCase(const MixedString : string) : string;

7.5. Example

7.5.1. Name

Converting a mixed case string to lower case

7.5.2. Code var

SimpleString : string;

begin

SimpleString := AnsiLowerCase('The Cat Sat on The MAT');

ShowMessage('SimpleString : '+SimpleString);

end;

7.5.3. Result SimpleString : the cat sat on the mat




Page 21 of 366

8. AnsiPos - Find the position of one string in another

8.1. Unit

SysUtils

8.2. Type

Function

8.3. Description

The AnsiPos function looks for a substring Needle in a string HayStack, returning the position

in the string of the first occurrence. All Ansi commands support multi-byte and accented

characters. if the string is not found, 0 is returned. The search is case sensitive.

8.4. Syntax function AnsiPos(const Needle, HayStack : string) : Integer;

8.5. Example

8.5.1. Name

Find a word in a sentence

8.5.2. Code var

position : Integer;

begin

// look for the word 'cat' in a sentence

// note : that this search is case sensitive, so that

// the first 'cat' is not matched

position := AnsiPos('Cat', 'The cat sat on the Cat mat');

if position = 0

then ShowMessage('''Cat'' not found in the sentence')

else ShowMessage('''Cat'' was found at character '+IntToStr(position));

end;

8.5.3. Result 'Cat' was found at character 20




Page 22 of 366

9. AnsiString - A data type that holds a string of AnsiChars

9.1. Unit

System

9.2. Type

Type

9.3. Description

The AnsiString data type is used to hold sequences of characters, like sentences. Each

character is an AnsiChar, guaranteed to be 8 bits in size. An AnsiString can hold any number of characters, restricted only by memory. Unlike ShortStrings, AnsiStrings are pointer

referenced variables. Storage is allocated for an AnsiString only when needed. for example,

assigning the value of one AnsiString to another does not allocate storage for a copy of the first string. Instead, the reference count of the first string is incremented, and the second

AnsiString set to point to it. But when the second string is changed, new storage is obtained for this new string, and the reference count for the first string is decremented. AnsiStrings

can be assigned from other strings, from functions that return a string, and with

concatenations as in the sample code.

9.4. Syntax type AnsiString;




Page 23 of 366

9.5. Example

9.5.1. Name

Assign to two AnsiStrings and manipulate these

9.5.2. Code var

string1, string2 : AnsiString;

begin

// assign a famous sentence to the first string

string1 := 'Hello World';

// assign to the second string

// this simply points string2 at string1

// the 'hello world' string storage has a reference count of 2

string2 := string1;

// add to the second string

// this disassociates from string1 - new string storage is

// created to hold the string2 value

string2 := string2 + ', how is everyone?';

// and finally, set the length of the first string to 5

SetLength(string1, 5);

// display both strings

ShowMessage('String1 = '+string1);

ShowMessage('String2 = '+string2);

end;

9.5.3. Result String1 = Hello

String2 = Hello World, how is everyone?




Page 24 of 366

10. AnsiUpperCase - Change lower case characters in a string to upper case

10.1. Unit

SysUtils

10.2. Type

Function

10.3. Description

The AnsiUpperCase function creates a copy of MixedString with all letters converted to upper

case. All Ansi commands support multi-byte and accented characters.

10.4. Syntax function AnsiUpperCase(const MixedString : string) : string;

10.5. Example

10.5.1. Name

Converting a mixed case string to upper case

10.5.2. Code var

SimpleString : string;

begin

SimpleString := AnsiUpperCase('The Cat Sat on The MAT');

ShowMessage('SimpleString : '+SimpleString);

end;

10.5.3. Result SimpleString : THE CAT SAT on THE MAT




Page 25 of 366

11. Append - Open a text file to allow appending of text to the end

11.1. Unit

System

11.2. Type

Procedure

11.3. Description

The Append procedure opens a file given by FileHandle to allow subsequent writes to append

to the end of the file. You must use AssignFile to assign a file to the FileHandle before using Append. This is often used when logging information - existing log data must be preserved,

with the new log information appended to the end. Use write or WriteLn to write to the file

after this Append is executed.

11.4. Syntax procedure Append(var FileHandle : TextFile);




Page 26 of 366

11.5. Example

11.5.1. Name

Appending a line of text to an existing file

11.5.2. Code var

myFile : TextFile;

text : string;

begin

// try to open the test.txt file for writing to

AssignFile(myFile, 'Test.txt');

ReWrite(myFile);

// write a couple of well known words to this file

WriteLn(myFile, 'Hello');

WriteLn(myFile, 'World');

// close the file

CloseFile(myFile);

// reopen to append a final line to the file

Append(myFile);

// write this final line

WriteLn(myFile, 'Final line added');

// close the file

CloseFile(myFile);

// reopen the file for reading

Reset(myFile);

// display the file contents

while not Eof(myFile) do

begin

ReadLn(myFile, text);

ShowMessage(text);

end;

// close the file for the last time

CloseFile(myFile);

end;

11.5.3. Result Hello

World

Final line added




Page 27 of 366

12. ArcCos - The Arc Cosine of a number, returned in radians

12.1. Unit

Math

12.2. Type

Function

12.3. Description

The ArcCos function is a mathematical function giving the value in radians of the Arc Cosine

of Number. PI radians = 180 degrees

12.4. Syntax function ArcCos(const Number : Extended) : Extended;

12.5. Example

12.5.1. Name

The ArcCos of 0.5 gives 60 degrees

12.5.2. Code var

float : single;

begin

// the arccos of 0.5 should give 60 degrees

float := ArcCos(0.5);

float := RadToDeg(float); // convert result to degrees

ShowMessage('ArcCos of 0.5 = '+FloatToStr(float)+' degrees');

end;

12.5.3. Result ArcCos of 0.5 = 60 degrees




Page 28 of 366

13. ArcSin - The Arc Sine of a number, returned in radians

13.1. Unit

Math

13.2. Type

Function

13.3. Description

The ArcSin function is a mathematical function giving the value in radians of the Arc Sine of

Number. PI radians = 180 degrees

13.4. Syntax function ArcSin(const Number : Extended) : Extended;

13.5. Example

13.5.1. Name

The ArcSin of 0.5 gives 30 degrees

13.5.2. Code var

float : single;

begin

// the arcsin of 0.5 should give 30 degrees

float := ArcSin(0.5);

float := RadToDeg(float); // convert result to degrees

ShowMessage('ArcSin of 0.5 = '+FloatToStr(float)+' degrees');

end;

13.5.3. Result ArcSin of 0.5 = 30 degrees




Page 29 of 366

14. ArcTan - The Arc Tangent of a number, returned in radians

14.1. Unit

System

14.2. Type

Function

14.3. Description

The ArcTan function is a mathematical function giving the value in radians of the Arc Tangent

of Number. PI radians = 180 degrees

14.4. Syntax function ArcTan(const Number : Extended) : Extended;

14.5. Example

14.5.1. Name

Get the ArcTan of PI/2

14.5.2. Code var

float : single;

begin

// the arctan of pi/2 should give 1.0

float := ArcTan(PI/2);

ShowMessage('ArcTan of PI/2 = '+FloatToStr(float));

end;

14.5.3. Result ArcTan of PI/2 = 1.00388479232788




Page 30 of 366

15. Array - A data type holding indexable collections of data

15.1. Unit

Iris Standard

15.2. Type

Keyword

15.3. Description

The array keyword provides single and multi dimensional arrays (indexable sequences) of

data. Arrays in Iris always have a fixed, unchangeable size. They may be single or multidimensional - the latter being an array of arrays (of arrays etc). The size and range of

such a multidimensional array is always given for the highest, leftmost array - the parent

array.

15.4. Syntax type Name = array[index type|Ordinal..Ordinal {,...}] of Base type;

15.5. Example 1

15.5.1. Name

Declaring and using arrays

15.5.2. Code var

IntArr : array[0..20] of integer;

i : Integer;

begin

// use indexing to furnish an array

for i := 5 to 20 do

IntArr[i] := i * 5;

// now use indexing to display 2 of the elements

ShowMessage('element 7 = '+IntToStr( IntArr[7] ));

ShowMessage('element 20 = '+IntToStr( IntArr[20] ));

end;

15.5.3. Result element 7 = 35

element 20 = 100




Page 31 of 366

15.6. Example 2

15.6.1. Name

Declaring and using multidimensional arrays

15.6.2. Code var

FloatArr : array[0..9,20..29] of single;

x,y : Integer;

begin

// use indexing to furnish an array

for x := 0 to 9 do

begin

for y := 20 to 29 do

FloatArr[x,y] := x+(y/100);

end;

// now use indexing to display 2 of the elements

ShowMessage('coordinate [3,24] = '+FloatToStr( FloatArr[3,24] ));

ShowMessage('coordinate [8,22] = '+FloatToStr( FloatArr[8,22] ));

end;

15.6.3. Result coordinate [3,24] = 3.24

coordinate [8,22] = 8.22




Page 32 of 366

16. AssignFile - Assigns a file handle to a binary or text file

16.1. Unit

System

16.2. Type

Procedure

16.3. Description

The AssignFile procedure assigns a value to FileHandle for a FileName in preparation for

reading or writing to that file. Takes a text file variable type as the handle. The file is treated

as a textfile when opened. if the file name is an empty string, then file access is made to the console standard input and output streams.

16.4. Syntax procedure AssignFile(var FileHandle : TextFile; const FileName : string);




Page 33 of 366

16.5. Example

16.5.1. Name

write to a text file, and then read back its contents

16.5.2. Code var

myFile : TextFile;

text : string;

begin



ReWrite(myFile);




// close the file

CloseFile(myFile);

// reopen the file for reading

Reset(myFile);



begin


ShowMessage(text);

end;


CloseFile(myFile);

end;


World




Page 34 of 366

17. Beep - Make a beep sound

17.1. Unit

SysUtils

17.2. Type

Procedure

17.3. Description

The Beep procedure creates a very short and quiet sound through the internal speaker of

your PC. It is used as an indication that the user has done something wrong.

17.4. Syntax procedure Beep;

17.5. Example

17.5.1. Name

Very simple!

17.5.2. Code begin

Beep;

end;

17.5.3. Result No result specified




Page 35 of 366

18. Begin - Keyword that starts a statement block

18.1. Unit

Iris Standard

18.2. Type

Keyword

18.3. Description

The begin keyword is fundamental to Iris - it starts statement blocks. The begin-end pair

fence in a set of statements. You may place such a block anywhere in your code. It is

particularly sensible in if and for statements, even if only one statement is required. It means that adding an additional statement in the future is easy.

18.4. Syntax begin

Statements

end

18.5. Example

18.5.1. Name

Some examples of the begin statement

18.5.2. Code var

myChars : array[1..2] of char;

myBytes : array[1..2] of Byte;

i : Integer;

// the begin statement always starts the code part of a subroutine

begin

// use a for block to assign to both arrays

for i := 1 to 2 do

begin

myChars[i] := Chr(i+64);

myBytes[i] := i+64;

end;

// use a for block to observe the contents

for i := 1 to 2 do

begin

ShowMessage('myChars['+IntToStr(i)+'] = '+myChars[i]);

ShowMessage('myBytes['+IntToStr(i)+'] = '+IntToStr(myBytes[i]));

end;

end;

18.5.3. Result myChars[1] = A

myBytes[1] = 65

myChars[2] = B

myChars[2] = 66




Page 36 of 366

19. Boolean - Allows just True and False values

19.1. Unit

System

19.2. Type

Type

19.3. Description

The Boolean type provides an enumeration of the logical True and False values. Unlike other

languages, it is not a number - it will only allow these values. This makes the code much

more reliable.

19.4. Syntax type Boolean = (False, True);

19.5. Example

19.5.1. Name

Boolean assignments and tests

19.5.2. Code var

same : Boolean;

small, large, i : Integer;

begin

small := 23;

large := 455555;

// test directly to see if these numbers are the same size

if small = large

then ShowMessage('small = large')

else ShowMessage('small large');

// use a boolean to hold and test this outcome

same := (small = large);

if same

then ShowMessage('small = large')

else ShowMessage('small large');

// assign a direct logical value to this boolean

same := True;

if same

then ShowMessage('same is True')

else ShowMessage('same is False');

end;

19.5.3. Result small large

small large

same is True




Page 37 of 366

20. Break - Forces a jump out of a single loop

20.1. Unit

System

20.2. Type

Procedure

20.3. Description

The Break procedure forces a jump out of the setof statements within a loop. Like the goto

statement, it should be used with caution. It is important to note that the Break statement

only jumps out of the current loop - not out of any nested loops above it. The goto statement can.

20.4. Syntax procedure Break;

20.5. Example

20.5.1. Name

Breaking out of a loop for good reason

20.5.2. Code var

i : Integer;

s : string;

begin

s := '';

// a big loop

for i := 1 to 10 do

begin

s := s + IntToStr(i) + ' ';

// exit loop when a certain condition is met

if Random(4) = 2 then Break;

end;

ShowMessage('i = '+IntToStr(i));

ShowMessage('s = '+s);

end;

20.5.3. Result i = 6

s = 1 2 3 4 5 6




Page 38 of 366

21. Byte - An integer type supporting values 0 to 255

21.1. Unit

System

21.2. Type

Type

21.3. Description

The Byte type is the smallest form of integer, occupying 8 bits (1 byte) of storage. It supports

only the positive integers from 0 to 255.

21.4. Syntax type Byte = 0..255;

21.5. Example

21.5.1. Name

Showing maximum and minimum byte values

21.5.2. Code var

A, B : Byte;

begin

// set the values of this data type

A := 5;

B := 100;

ShowMessage('A = '+IntToStr(A)+' and B = '+IntToStr(B));

ShowMessage('A + B = '+IntToStr(A+B));

end;

21.5.3. Result A = 5 and B = 100

A + B = 100




Page 39 of 366

22. Cardinal - The basic unsigned integer type

22.1. Unit

System

22.2. Type

Type

22.3. Description

The Cardinal type is an Integer whose size is not guaranteed. It is the basic unsigned integer

type, and currently has the same capacity as the LongWord: 32 bits. to hold very large

integers, use the Int64 type.

22.4. Syntax type Cardinal = 0..4294967295; // at the time of writing

22.5. Example

22.5.1. Name

Showing the capacity of Cardinal

22.5.2. Code var

A, B : Cardinal;

begin

// set the values of this data type

A := 1;

B := 999999;

ShowMessage('A = '+IntToStr(A)+' and B = '+IntToStr(B));

ShowMessage('A + B = '+IntToStr(A+B));

end;

22.5.3. Result A = 1 and B = 999999

A + B = 1000000




Page 40 of 366

23. Case - A mechanism for acting upon different values of an Ordinal

23.1. Unit

Iris Standard

23.2. Type

Keyword

23.3. Description

The case keyword provides a structured equivalent to a sequence of if statements on the

same variable. The case statement is more elegant, more efficient, and easier to maintain than multiple if nestings.

23.4. Syntax 1 case Ordinal expression of

Ordinal value {,ordinal value...} : Statement;

{...}

else Statement;

end;




Page 41 of 366

23.5. Example

23.5.1. Name

Standard case statement usage


// procedure showcolour(colour : string);

var

colour : string;

number : Integer;

begin

// show the colour before it has an assigned value

ShowColour(colour);

// now set the colour and try again

colour := 'Green';

ShowColour(colour);

// calculations can also be used in the case statement

number := 17;

case number mod 2 of

0 : ShowMessage(IntToStr(Number)+' mod 2 = 0');

1 : ShowMessage(IntToStr(Number)+' mod 2 = 1');

else ShowMessage(IntToStr(Number)+' mod 2 is unknown');

end;

end;

// procedure to show the colour of a passed

procedure TUntitled.ShowColour(colour : string);

begin

// use a case statement to see the colour of the passed var

// note how important the else clause is, even though we have

// apparently covered all string values!

case colour of

'Red' : ShowMessage('The colour is Red');

'Green' : ShowMessage('The colour is Green');

'Blue' : ShowMessage('The colour is Blue');

'Yellow' : ShowMessage('The colour is Yellow');

else ShowMessage('The colour is Unknown!');

end;

end;

23.5.3. Result The colour is Unknown!

The colour is Green

17 mod 2 is 1




Page 42 of 366

24. ChangeFileExt - Change the extension part of a file name

24.1. Unit

SysUtils

24.2. Type

Function

24.3. Description

The ChangeFileExt function changes the Extension value of a file FileName, returning the new

value as a string.

24.4. Syntax function ChangeFileExt(const FileName, Extension : string) : string;

24.5. Example

24.5.1. Name

Renaming Test.exe to Test.bak

24.5.2. Code var

oldName, newName : string;

begin

// try to rename the current test.exe to test.bak

oldName := 'Test.exe';

newName := ChangeFileExt(oldName, '.bak');

// show the old and new values

ShowMessage('Old name = '+oldName);

ShowMessage('New name = '+newName);

end;

24.5.3. Result Old name = Test.exe

New name = Test.bak




Page 43 of 366

25. ChangePage - Change a page

25.1. Unit

Iris Standard

25.2. Type

Frame Function

25.3. Description

Opens a new screen instead of the active screen

25.4. Syntax procedure ChangePage(PageName: string);

25.5. Example 1

25.5.1. Name

Open the screen 'ScreenName'

25.5.2. Code begin

ChangePage('ScreenName');

end;


25.6. Example 2

25.6.1. Name

Open the screen 'ScreenName' in the frame 'FrameName'

25.6.2. Code begin

FrameName.ChangePage('ScreenName');

end;





Page 44 of 366

26. Char - Variable type holding a single character

26.1. Unit

System

26.2. Type

Type

26.3. Description

The Char type is a simple variable type used to hold a single character. It can be assigned

from a character constant, or an integer.

26.4. Syntax type : Char = #0..#255;

26.5. Example

26.5.1. Name

Different ways of assigning to and from a Char

26.5.2. Code var

myChar : Char;

begin

myChar := 'g'; // assign from a character constant

ShowMessage('Letter g = '+myChar);

myChar := #65; // assign from an integer constant

ShowMessage('#65 = '+myChar);

myChar := Chr(66); // using chr to convert a number

ShowMessage('Chr(66) = '+myChar);

end;

26.5.3. Result Letter g = g

#65 = A

Chr(66) = B




Page 45 of 366

27. ChDir - Change the working drive plus path for a specified drive

27.1. Unit

System

27.2. Type

Procedure

27.3. Description

The ChDir procedure sets the working drive + path values to the supplied Directory. There

are as many working directories as drives on the target machine. if the directory is invalid, you will get an error such as ElnOutError, and the directory will remain unchanged.

27.4. Syntax procedure ChDir(const Directory : string);

27.5. Example

27.5.1. Name

Getting and setting the directory for the C: drive

27.5.2. Code var

directory : string;

begin

// get the directory for the c drive

GetDir(2, directory);

ShowMessage('default C drive directory = '+directory);

// set the c directory to this value

ChDir(directory);



// try to set to an invalid value

ChDir('C:Bad/Path/Value');



end;

27.5.3. Result The following output is representative, and will necessarily vary

from PC to PC:

C:\IrisTest

C:\IrisTest

EInOutError ('Invalid file name')

IrisTest




Page 46 of 366

28. Chr - Convert an integer into a character

28.1. Unit

System

28.2. Type

Function

28.3. Description

The Chr function converts an IntValue integer into either an AnsiChar or WideChar as

appropriate.

28.4. Syntax function Chr(IntValue : Integer) : AnsiChar;

28.5. Example

28.5.1. Name

Showing Chr usage

28.5.2. Code var

tab : char;

crlf : string;

begin

// show the use of chr

tab := Chr(9);

crlf := Chr(13)+Chr(10);

ShowMessage('Hello'+tab+'World');

ShowMessage('');

ShowMessage('Hello'+crlf+'World');

ShowMessage('');

end;

28.5.3. Result Hello World

Hello

World




Page 47 of 366

29. ClearMailBox - Clears the current MailBox

29.1. Unit

Iris Standard

29.2. Type

MailBox Function

29.3. Description

Clears the current mailbox. MailBoxes can be used to pass structrured values to for example

popups.

29.4. Syntax procedure ClearMailbox;

29.5. Example

29.5.1. Name

Using MailBoxes

29.5.2. Code begin

// set the mailbox 'mymailbox' to the object 'unit23'

SetMailBox('MyMailBox','Unit23')

// the following could be done in a linked popup

// write a value to the tag '[mymailbox].open', - which will be unit23.open

WriteTagValue(ExpandMailbox('[MyMailBox].Open'),1);

// remove the mailbox

RemoveMailbox('MyMailBox')

// the following could be done in another linked popup

// set the mailbox 'mymailbox' to the object 'unit23.modulea'

SetMailBox('MyMailBox','Unit23.ModuleA')

// write a value to the tag '[mymailbox].status', - which will be unit23.modulea.status

WriteTagValue(ExpandMailbox('[MyMailBox].Open'),0);

// clear the current mailbox

ClearMailbox;

end;

29.5.3. Result

Unit23.Open is written inside popup 1

Unit23.ModuleA.Status is written inside popup 2 that is a popup from popup 1




Page 48 of 366

30. CloseCurrentPage - Close a screen

30.1. Unit

Iris Standard

30.2. Type

Frame Function

30.3. Description

Closes the active screen. Note that this can also be a popup screen.

30.4. Syntax procedure CloseCurrentPage;

30.5. Example

30.5.1. Name

Close the current screen

30.5.2. Code begin

// closes the screen

CloseCurrentPage;

end;





Page 49 of 366

31. CloseFile - Closes an open file

31.1. Unit

System

31.2. Type

Procedure

31.3. Description

The CloseFile procedure closes an open file given by FileHandle. The file must have been

assigned, and opened with Append, Reset or ReWrite. The file is closed, and the handle is

made available for further assignment to files.

31.4. Syntax procedure CloseFile(var FileHandle : TextFile);




Page 50 of 366

31.5. Example

31.5.1. Name

Closing after write and read operations

31.5.2. Code var

myFile : TextFile;

text : string;

begin



ReWrite(myFile);




// close the file

CloseFile(myFile);

// reopen the file in read only mode

Reset(myFile);



begin


ShowMessage(text);

end;


CloseFile(myFile);

end;


World




Page 51 of 366

32. CompareStr - Compare two strings for equality

32.1. Unit

SysUtils

32.2. Type

Function

32.3. Description

The CompareStr function compares String1 and String2 for equality. It returns these values :

String1 < String2 : -ve numberString1 = String2 : 0String1 > String2 : +ve number The

comparison is not affected by length - it is carried out on a letter by letter basis. But a longer string is greater than a shorter, otherwise matching string. The comparison is case sensitive.

32.4. Syntax function CompareStr(const String1, String2 : string) : Integer;




Page 52 of 366

32.5. Example

32.5.1. Name




begin





// upper case letters follow lower case in iris

CompareStrings('ABC', 'abc');



end;



var

result : Integer;

begin


result := CompareStr(string1, string2);




end;


Hi 2 you = Hi 2 you

ABC > abc

abc > 123




Page 53 of 366

33. CompareText - Compare two strings for equality, ignoring case

33.1. Unit

SysUtils

33.2. Type

Function

33.3. Description

The CompareText function compares String1 and String2 for equality, ignoring case. It

returns these values : String1 < String2 : -ve numberString1 = String2 : 0String1 > String2 : +ve number The comparison is not affected by length - it is carried out on a letter by letter

basis. But a longer string is greater than a shorter, otherwise matching string.

33.4. Syntax function CompareText(const String1, String2 : string) : Integer;




Page 54 of 366

33.5. Example

33.5.1. Name




begin





// ansicomparetext treats upper and lower case identically

CompareStrings('ABCdef', 'abcDEF');



end;



var

result : Integer;

begin


result := CompareText(string1, string2);




end;


Hi 2 you = Hi 2 you

ABCdef = abcDEF

abc > 123




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34. CompareValue - Compare numeric values with a tolerance

34.1. Unit

Math

34.2. Type

Function

34.3. Description

CompareValue allows floating point numbers to be compared in a tolerant way. if the two

numbers are close enough together, they are deemed to be equal. The delta value is the permitted tolerance. There seems no point to the author in providing the Integer version of

this function with no delta. TValueRelationship supports the following values: LessThanValue

-1EqualsValue 0GreaterThanValue 1

34.4. Syntax function CompareValue (const A, B : Single|Double|Extended; delta : Single|Double|Extended) : TValueRelationship;




Page 56 of 366

34.5. Example

34.5.1. Name

Comparing floating point numbers

34.5.2. Code var

A : Single;

B : Single;

C : Single;

begin

A := 23.0;

B := 23.0;

C := 23.1;

// compare 2 equal floats

case CompareValue(A, B, 0) of

LessThanValue : ShowMessage('A < B');

EqualsValue : ShowMessage('A = B');

GreaterThanValue : ShowMessage('A > B');

end;

// compare 2 unequal floats

case CompareValue(A, C, 0) of

LessThanValue : ShowMessage('A < C');

EqualsValue : ShowMessage('A = C');

GreaterThanValue : ShowMessage('A > C');

end;

// compare 2 unequal floats - but allow for a difference of up to +/- 0.2

case CompareValue(A, C, 0.2) of

LessThanValue : ShowMessage('A < C');

EqualsValue : ShowMessage('A = C');

GreaterThanValue : ShowMessage('A > C');

end;

end;

34.5.3. Result A = B

A < C

A = C




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35. Const - Starts the definition of fixed data values

35.1. Unit

Iris Standard

35.2. Type

Keyword

35.3. Description

The const keyword is used to start a section of constant definitions. The section is terminated

by the next keyword in a program. Within the section, one or more constants may be

defined.

35.4. Syntax const Name1 = Expression1;

35.5. Example

35.5.1. Name

Illustrating the different constant types

35.5.2. Code const

MAX_LINES = 3;

CRUDE_PI = 22/7;

HELLO = 'Hello World';

var

i : Integer;

begin

// display our crude value of pi

ShowMessage('Crude Pi = '+FloatToStr(CRUDE_PI));

// say hello to the world

ShowMessage(HELLO);

// display max_lines of data

for i := 1 to MAX_LINES do

ShowMessage(Chr(i+64));

end;

35.5.3. Result Crude Pi = 3.14285714285714

Hello World

A

B

C




Page 58 of 366

36. Continue - Forces a jump to the next iteration of a loop

36.1. Unit

System

36.2. Type

Procedure

36.3. Description

The Continue procedure forces a jump past the remaining statements within a loop, back to

the next loop iteration. Like the goto statement, it should be used with caution. It is

important to note that the Continue statement only jumps to the start of the current loop - not out of any nested loops above it. The goto statement can.

36.4. Syntax procedure Continue;

36.5. Example

36.5.1. Name

Skipping loop processing for certain loop values

36.5.2. Code var

i : Integer;

s : string;

begin

s := '';

// a big loop

for i := 1 to 9 do

begin

// skip loop processing for certain values of i

if (i = 3) or (i = 7) the

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