Recursive descent parser: Difference between revisions

Revision as of 02:38, 6 March 2006

Revision as of 13:25, 6 March 2006

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[[Terminals]] are expressed in quotes (except for the well defined ''ident''

and ''number''). Each [[nonterminal]] is defined by a rule in the grammar.

Notice how closely the code below mirrors the grammar above. There is a procedure for each nonterminal in the grammar. Parsing descends in a top-down manner, until the final nonterminal has been processed. The program fragment depends on a global variable, ''sym'', which contains the next symbol from the input, and the global function ''getsym'', which updates ''sym'' when called.