Type system

ezc is dynamically typed. Every value carries its type at runtime and operators check types when popping.

Value types

Numeric families

Arithmetic operators only work between values in the same family:

• Integer family — int
• Unsigned family — u8, u16, ..., u256
• Signed family — i8, i16, ..., i256
• Float family — f16, f32, f64

Within a family, operations promote to the wider type:

3u8 4u32 +    # → 7u32 (u8 promoted)

Cross-family is an error — int, unsigned, signed, and float are separate families. Convert explicitly:

3 4u8 +        # error: int and u8 are different families
3 u8 4u8 +     # → 7u8  (convert 3 to u8 first)

int (BigInt) is its own family. Within int, all ops are exact:

2 100 ^        # 2^100 as int (no overflow)

Fixed-width types overflow (and error) when results exceed their range:

2u8 7u8 ^      # 128u8 — fits
2u8 8u8 ^      # error: overflow in u8

Truthiness

Used by ?, ??, & and the higher-order ops:

Interning

str, bin, and int (BigInt) values are interned per engine instance. Equality is constant-time pointer comparison; copying is shared via Arc. This makes large strings and integers cheap to pass around.

Spans

Every value on the stack carries a source span — the byte range of the expression that pushed it. The DAP debugger and ariadne error reports use these spans to highlight the exact token responsible for a mismatch, not just a line number.