Difference between revisions of "NML:Elementary values"

From GRFSpecs
Jump to navigationJump to search
m (Reverted edits by Andythenorth (talk) to last revision by Frosch)
Tag: Rollback
Line 51: Line 51:
 
* Bitwise/logic operators: &, |, ^, &&, ||, <<, >>
 
* Bitwise/logic operators: &, |, ^, &&, ||, <<, >>
 
* Comparison operators: ==, !=, <=, >=, <, >
 
* Comparison operators: ==, !=, <=, >=, <, >
  +
* Ternary operator: ? : (only for integers)
 
'''Ternary operator'''
 
 
A ternary operator is provided (for integers only) in the form:
 
 
condition ? branch if true : branch if false
 
 
The ternary operator should be used with caution:
 
* it can be inefficient in certain cases as it executes both branches
 
* it is only safe for readonly operations (i.e. cannot be used with expressions like STORE_TEMP or STORE_PERM)
 

Revision as of 10:00, 28 August 2022

Elementary values in expressions are

Element Syntax (Python RE) Description
Decimal number [0-9]+ one or more digits
Hexadecimal number 0x[0-9A-Fa-f]+ "0x" followed by one or more hexadecimal digits
Floating point number [0-9]+\.[0-9]+ a decimal number, a dot, and another decimal number. Only supported for some properties that expect a floating point number.
Identifier [a-zA-Z_][a-zA-Z0-9_]* a letter or underscore, optionally followed by more letters, digits, or underscore characters
String "([^"\\]|\\.)*" A double quote character, followed by zero or more characters, ending with another double quote character. A character in-between is any single character except a double quote or a back-slash ("\"). It can also be "\\", "\n", "\t", or "\[0-9A-Fa-f][0-9A-Fa-f]" (a back-slash followed by exactly two hexadecimal digits).
Setting an Identifier

The name of a GRF setting

Parameter param[<num>] Read/write the parameter with the given number.
Parameter from another GRF param[<grfid>, <num>] Read the value of a parameter of another grf
Unit mph|km/h|m/s|hp|kW|hpI|hpM|tons|ton|kg

See the section on units.

You can combine those elementary values using operators like you're used to from other languages. The following operators are supported:

  • Arithmetic operators: +, -, *, /, %
  • Bitwise/logic operators: &, |, ^, &&, ||, <<, >>
  • Comparison operators: ==, !=, <=, >=, <, >
  • Ternary operator: ? : (only for integers)