Syntactic Analysis:The Parser

• A Parser: reads (token,lexeme) pairs from the Scanner and recognizes the tokens in the grammar of the language

• builds a parse tree, corresponding to the grammar, for the semantic analyser

• determines the structure of the language

• doesn’t know about the characters that make up the language (Scanner)

• doesn’t know anything about the meaning of the grammar (Semantics)

• usually recursive, e.g. to handle nesting

  • parentheses: S := ‘(’ expr ‘)’
  • blocks: BEGIN, END