suzanne.soy/racket
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Gracefully handle the case where the token stream just contains the END token and an error occurs.

Browse Source
This commit is contained in:
Danny Yoo 2013-01-11 13:59:18 -07:00
parent f93c620814
commit 69ae77a253
1 changed files with 21 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
collects/algol60/cfg-parser.rkt
View File

@ -744,19 +744,31 @@
val
(next success-k fail-k max-depth tasks)))]
[fail-k (lambda (max-depth tasks)
(let ([bad-tok (list-ref tok-list
(min (sub1 (length tok-list))
max-depth))])
(cond
[(null? tok-list)
(if error-proc
(error-proc #t
(tok-orig-name bad-tok)
(tok-val bad-tok)
(tok-start bad-tok)
(tok-end bad-tok))
'no-tokens
#f
(make-position #f #f #f)
(make-position #f #f #f))
(error
'cfg-parse
"failed at ~a"
(tok-val bad-tok)))))])
"no tokens"))]
[else
(let ([bad-tok (list-ref tok-list
(min (sub1 (length tok-list))
max-depth))])
(if error-proc
(error-proc #t
(tok-orig-name bad-tok)
(tok-val bad-tok)
(tok-start bad-tok)
(tok-end bad-tok))
(error
'cfg-parse
"failed at ~a"
(tok-val bad-tok))))]))])
(#,start tok-list
;; we simulate a token at the very beginning with zero width
;; for use with the position-generating code (*-start-pos, *-end-pos).