gforth/kernel/recognizer.fs - diff

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version 1.20, 2012/06/23 23:20:23	version 1.21, 2012/07/02 21:59:48
Line 25	Line 25
\ The "design pattern" used here is the factory, even though	\ The "design pattern" used here is the factory, even though
\ the recognizer does not return a full-blown object.	\ the recognizer does not return a full-blown object.
\ A recognizer has the stack effect	\ A recognizer has the stack effect
\ ( addr u -- token table true \| addr u false )	\ ( addr u -- token table \| addr u r:fail )
\ where the token is the result of the parsing action (can be more than	\ where the token is the result of the parsing action (can be more than
\ one stack or live on other stacks, e.g. on the FP stack)	\ one stack or live on other stacks, e.g. on the FP stack)
\ and the table contains for actions (as array of four xts:	\ and the table contains three actions (as array of three xts):
\ interpret it, compile interpretation semantics	\ interpret it, compile it, compile it as literal.
\ compile it, compile it as literal.

: recognizer: ( xt1 xt2 xt3 -- ) Create rot , swap , , ;	: recognizer: ( xt1 xt2 xt3 -- ) Create rot , swap , , ;