Expressions

Expression is scripting language used in PlanetCNC TNG.

• Expression is used with scripts, e.g. Expr.txt. Such files contain script code which is evaluated by PlanetCNC TNG expression evaluator.
• It can be very practical for PLC type applications where periodical evaluation is necessary or for program events.
• Expr.txt file can contain and use vast array of expression functions, parameters and other commands supported by PlanetCNC TNG.
• Expr.txt file is located in the profile folder of TNG software.
• Profile folder can contain multiple Expr.txt files. Specific Expr file naming convention is available for better distinction. e.g.: Expr_Semaphore
• If multiple expr files use same function, then function will be called first from the first file and only then with the next file.
• Local variables(e.g. name convention of local variables: red_light, global variables: _red_light ) have scope only within the parent Expr file.
• Each Expr file contains functions that are marked with symbol #.
• Each function begins with symbol # and ends with the next # symbol.
• Each expr file can use built-in functions that are related with program events