📦 ctoml

Simple single header parsing library for TOML files.

🚀 Build & Run

./build.sh

❌ Error Handling Strategy

The lexer and parser split error responsibility by layer:

Lexer — Character-Level Errors

The lexer rejects tokens that are structurally malformed in isolation, regardless of position in the grammar.

Error	Example	Token
Invalid character	bare \r, \x00	TOK_INVALID
Invalid escape sequence	\q, \uDFFF	TOK_INVALID
Unterminated string	"hello at EOF	TOK_INVALID
Invalid numeric structure	23abc, 1__0	TOK_INVALID

Parser — Sequence-Level Errors

The parser rejects token sequences that are invalid in context, where the lexer has no way of knowing whether a token is meaningful without grammar context.

Error	Example
Invalid value start	key = .7
Missing =	key value
Duplicate keys	key = 1 then key = 1
Malformed table header	[[key]

Rationale

The lexer operates statelessly on individual tokens — it rejects what is never valid as a token. The parser operates on sequences — it rejects what is not valid in position. .7 for example is two valid tokens (TOK_DOT + TOK_INTEGER); only the parser knows that a dot is not a legal value start.