grmtools

The syntax of the lrlex .l format, aims to be familiar to the format used by posix lex. It uses the same basic structure as lex.

Definitions
%%
Rules
%%
User Subroutines

Definitions

Within the definitions section, you can add an option %grmtools section documented in extensions

Rules

Each rule is given by the following elements in sequence:

1. Optional Start State, one or more names comma separated between angle brackets. For example <Start_State> documented in Start States.
2. Regex, syntax defined by the rust regex crate with optional escaping for any character.
3. Separator space, any horizontal space character in the unicode Pattern_White_Space character set
4. Optional State operator, given between angle brackets documented in Start States
   • <+STATE> Push the state given by STATE to the top of the stack.
   • <-STATE> Pop the state off the top of the stack.
   • <STATE> Replace the state stack with the state STATE
5. Token Name, for example "token" any non-space character between double quotes, including double quotes.
6. End of line, finishes each rule.

User Subroutines

Since lrlex doesn’t support user actions, it doesn’t support User Subroutines either.