Lex extensions
Flags can be specified at compile time through LexFlags or at .l file parse time using
a %grmtools{ } section. At compile time these flags can be enabled using
CTLexerBuilder methods.
Flags commonly affect the parsing of the lex file, the interpretation regular expressions, and set limits.
Boolean flags are specified by their name, and can be negated by prefixing with !
other flags should specify their value immediately after the flag name.
Example
%grmtools {
allow_wholeline_comments,
!octal,
size_limit: 1024,
}
%%
. "rule"
List of flags:
| Flag | Value | Required |
|---|---|---|
lrlex.lexerkind | LexerKind | ✗ |
lrlex.posix_escapes1 | bool | ✗ |
lrlex.allow_wholeline_comments2 | bool | ✗ |
regex.case_insensitive | bool | ✗ |
regex.dot_matches_new_line | bool | ✗ |
regex.multi_line | bool | ✗ |
regex.octal | bool | ✗ |
regex.swap_greed | bool | ✗ |
regex.ignore_whitespace | bool | ✗ |
regex.unicode | bool | ✗ |
regex.size_limit | usize | ✗ |
regex.dfa_size_limit | usize | ✗ |
regex.nest_limit | u32 | ✗ |
Flags affecting Posix compatibility
As discussed in Lex compatibility the default behaviors of grmtools and rust’s regex library have differed from that of posix lex.
The following flags can change the behavior to match posix lex more closely.
%grmtools {
!dot_matches_new_line,
posix_escapes
}
%%
...