constant

Typecommand
DictionaryLCS
LibraryLiveCode Script
Syntax
constant <constantsList>
Summary

Declares one or more labels to assign to constant values.

Introduced1.0
OSmac, windows, linux, ios, android
Platformsdesktop, server, mobile
Parameters
NameTypeDescription
constantsList

The constantsList consists of one or more 'name=value' pairs, separated by commas:

  • The 'name' is any string.
  • The 'value' is any literal string.
Example
constant kDefaultName="Jones"
constant kEntryA="EF9993333WX786",kEntryB="GJ773281YX342"
RelatedProperty: script
Constant: watch, false, slash, comma, plus, null, pi, iBeam, colon, three, formfeed, help, five, zero, seven, eight, CRLF, quote, empty, space, arrow, six, ten, four, two
Command: constant, local
Function: constantNames
Control Structure: function
Glossary: LiveCode, value, handler, string, statement, constant, keyword, command
Description

Use the constant command to assign an unchanging value to a keyword.

Constants can be numbers, characters, logical values, or strings.

A constant cannot be defined as an array, only as a single value.

Note: Choose easy-to-understand names for constants to improve the readability of your code. Use constants as substitutes for long or convoluted strings. Use the prefix letter k for your constant names to follow convention and make it easy to recognise. See the Tips For Writing Good Code in the Livecode Script Guide.

If you place the constant statement in a handler, you can use the constant anywhere in the handler. If you place the constant statement in a script outside any handler, you can use the constant anywhere in the handlers of that script.

Once you have defined a constant, you cannot redefine it in the same handler; doing so causes an execution error.

You can use the constant command to redefine LiveCode's built-in constants within a script or handler, but doing so makes your code harder to read and maintain. To find out whether a word is already defined as a built-in constant, use the constantNames function.

Tip: To see a list of built-in constants, open the Documentation window, click LiveCode Dictionary, and choose "Constants" from the menu at the top of the window.

Tagsproperties