Lexical Structure

Before Coldwave Script can execute a program, the source text must be lexically analyzed. The text is broken down into the smallest units (tokens): keywords, identifiers, literals, operators, and comments. Understanding these building blocks helps prevent errors at the writing stage and clarifies how the language is designed.

Keywords

Keywords are reserved words with fixed meaning. They may not be used as variable names.

Examples:

PROGRAM, END PROGRAM, DIM, CONST, IF, THEN, ELSE,
END IF, FOR, WHILE, DO, LOOP, NEXT, FUNCTION, END FUNCTION,
SUB, END SUB.

Example:

PROGRAM  
    DIM a AS INT = 5  
    IF a > 0 THEN  
         PRINT "a is positive"  
    END IF  
END PROGRAM

Identifiers

Identifiers are names for variables, constants, or block instances.

Rules:

• Must begin with a letter (A-Z, a-z).
• May contain letters, digits, or _ afterwards.
• No umlauts or special characters.
• Case-sensitive (Counter ≠ counter).

Example:

PROGRAM  
    DIM Counter AS INT = 0  
    DIM T AS TON  
    PRINT Counter  
END PROGRAM

Literals

Numbers: 42, -123, 0xFF, 3.14, 1.2E6
Strings: "Hello World" (supports \n, \t)
Time formats: T#500ms, DATE#2025-01-01, TOD#12:00:00, DT#2025-01-01-12:00:00

PROGRAM  
    DIM i AS INT = 42  
    DIM pi AS REAL = 3.14159  
    DIM text AS STRING = "Example"  
    DIM t AS TIME = T#2s  
    PRINT i, pi, text, t  
END PROGRAM

Operators

Arithmetic: +, -, *, /, MOD
Bitwise: SHL, SHR, AND, OR, XOR, NOT
Comparison: =, <>, <, <=, >, >=

PROGRAM  
    DIM a AS INT = 5  
    DIM b AS INT = 2  
    PRINT a / b ' Output: 2 (integer division)  
    PRINT a MOD b ' Output: 1  
    PRINT a SHL 1 ' Output: 10 (binary 101 → 1010)  
END PROGRAM

Comments

Comments document code and are ignored by the interpreter. They begin with ' or REM.

PROGRAM  
    ' This program counts to 3  
    DIM i AS INT  
    FOR i = 1 TO 3  
    PRINT i  
    NEXT i  
END PROGRAM

Summary

• Keywords are reserved and cannot be used as names.
• Identifiers have defined rules and are case-sensitive.
• Literals include numbers, strings, and time types.
• Operators cover arithmetic, bitwise operations, and comparisons.
• Comments improve readability and are ignored during execution.