Crate rusty_lr

RustyLR

LR(1) and LALR(1) code generator in Rust

For sample and examples, please refer to the GitHub repository

Features

• pure Rust implementation
• compile-time DFA construction from CFGs ( with proc-macro )
• customizable reducing action
• resolving conflicts of ambiguous grammar
• tracing parser action with callback, also error handling
• readable error messages, both for grammar building and parsing

Why proc-macro, not external executable?

• Decent built-in lexer, with consideration of unicode and comments.
• Can generate pretty error messages, by just passing Span data.
• With modern IDE, can see errors in real-time with specific location.

Macros

• lalr1
  build a lalr1 Deterministic Finite Automaton (DFA) parser at compile time
• lalr1_runtime
  build a lalr1 Deterministic Finite Automaton (DFA) parser at runtime
• lr1
  build a lr1 Deterministic Finite Automaton (DFA) parser at compile time
• lr1_runtime
  build a lr1 Deterministic Finite Automaton (DFA) parser at runtime

Structs

• Context
  struct for parsing context
• DefaultCallback
  default callback that does nothing
• Grammar
  A struct for Context Free Grammar and DFA construction
• LookaheadRuleRefSet
  set of lookahead rules
• Parser
  struct for Deterministic Finite Automaton (DFA).
• ProductionRule
  Production rule.
• ShiftedRuleRef
  A struct for single shifted named production rule.
• State
  state in DFA

Enums

• BuildError
  Error type for grammar.build()
• ParseError
  Error type for feed()
• ReduceType
  for resolving shift/reduce conflict
• Token
  Token represents a terminal or non-terminal symbol in the grammar.

Traits

• Callback
  callback trait for tracing parser actions