Language Syntax

Language Syntax

CupidScript uses a C-like surface syntax.

Comments

Supported comment forms:

// line comment

/* block comment */

Comments are skipped by the lexer alongside whitespace.

Tokens

Identifiers

• Start: letter or _
• Continue: letters, digits, _

Integers

Decimal and hexadecimal integers with optional underscores:

0
12345
1_000_000
0xFF
0xFF_FF_FF

• Decimal: 0-9 digits
• Hexadecimal: 0x or 0X followed by hex digits (0-9, a-f, A-F)
• Underscores _ can appear anywhere in the number (ignored)

Floats

Floating-point literals with decimal point:

3.14
2.5
0.001
1.5e-3
2.0E+10

• Must contain a decimal point: .
• Optional exponent: e or E followed by optional +/- and digits
• Scientific notation: 1.5e-3 equals 0.0015

Strings

Double-quoted strings:

"hello"
"with \n escapes"
"quote: \""
"backslash: \\"

Escape handling (in runtime unescape):

• \n, \t, \r, \", \\
• Any unknown escape \x becomes literal x

List Literals

[]
[1, 2, 3]
["a", "b", "c"]

Map Literals

{}
{"name": "Frank", "age": 30}
{"key": value_expr}

Keys must be string expressions (can be any expression that evaluates to a string).

Operators & Punctuation

Punctuation

( ) [ ] { } , ; .

Operators

Assignment:

• =
• +=, -=, *=, /= (compound assignment)

Arithmetic:

• + - * / %

Unary:

• ! -

Comparison:

• == != < <= > >=

Boolean:

• && ||

Range:

• .. (exclusive range, e.g., 0..5 → [0,1,2,3,4])
• ..= (inclusive range, e.g., 0..=5 → [0,1,2,3,4,5])

Precedence (high to low)

1. Primary: literals, identifiers, parenthesized (expr), list literals [...], map literals {...}
2. Postfix: calls f(...), indexing a[b], field access a.b
3. Unary: !expr, -expr
4. Multiplicative: * / %
5. Additive: + -
6. Range: start..end, start..=end
7. Comparison: < <= > >=
8. Equality: == !=
9. AND: &&
10. OR: ||
11. Ternary: cond ? then : else