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Infinite left recursion now causes a failed parser rather than a call stack error

release
Chris Double 2007-11-30 00:01:03 +13:00
parent 3003911e07
commit 38beaac720
1 changed files with 5 additions and 1 deletions
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6
extra/peg/peg.factor
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@ -52,7 +52,11 @@ PRIVATE>
packrat-cache get [ packrat-cache get [
2dup get-cached dup not-in-cache? [ 2dup get-cached dup not-in-cache? [
! "cache missed: " write over parser-id number>string write " - " write nl ! pick . ! "cache missed: " write over parser-id number>string write " - " write nl ! pick .
drop [ (parse) dup ] 2keep put-cached drop
#! Protect against left recursion blowing the callstack
#! by storing a failed parse in the cache.
[ f ] dipd [ put-cached ] 2keep
[ (parse) dup ] 2keep put-cached
] [ ] [
! "cache hit: " write over parser-id number>string write " - " write nl ! pick . ! "cache hit: " write over parser-id number>string write " - " write nl ! pick .
2nip 2nip