[REBOL] Strange parsing behavior
From: robert:muench:robertmuench at: 2-Aug-2002 19:27
Hi, please have a look at this code and try it out:
---START
rebol []
rule1: [start: copy string1 [to " - " (?? string1) | to newline] copy
string2 to end]
rule2: [start: copy string1 [to " - " (?? string1) 3 skip | to newline]
copy string2 to end]
text: "this is a - parsing test"
parse/all text rule1
?? string1
?? string2
print "-----"
parse/all text rule2
?? string1
?? String2
---END
>> do %parsing-error.r
string1: "this is a - "
string1: "this is a"
string2: " - parsing test"
-----
string1: "this is a"
string1: "this is a - "
string2: "parsing test"
== "parsing test"
I find some things very strange here:
Rule1:
- Why does string1 contain " - " when printed from inside
the rule? The rule states 'to and not 'thru? IMO string1
should be "this is a"
- After the parsing string1 holds what I did expect in the
first place too. This indicates that the varaibles input
gets copied to will be changed after the parsing. But when and how?
Rule2:
- This time the string1 is as expected inside the rule but
changes to include the to " - " sequence after the parsing
Any idea what's up here? Is this a bug? Robert
