Clever Geek Handbook

Flex logic / C ++ regex error

I have done my best to include all (and only) the information you need. Let me know if seeing more can help you help me.

I am having problems with my regex. My program prints in lexeme-token pairs of a .txt file. Everything works fine except for IDs and integers. For example, the token for the ID is 262.

Sample input file:

function main a: integer returns integer;
    b: integer is a * 2;

Output example:

function - 269
maina - 262
integer - 272
returns - 274
integer - 272
; - 59
b - 262
integer - 272
is - 271
a - 262
2 - 263
; - 59

Correct conclusion:

function - 269
main - 262
a - 262
: - 58
integer - 272
returns - 274
integer - 272
; - 59
b - 262
: - 58
integer - 272
is - 271
a - 262
* - 261
2 - 263
; - 59

To summarize, it concatenates the two space-separated IDs and also removes any token after the ID.

+3


source to share


1 answer


You just forgot to put curly braces around some names. Instead

{letter}(letter|digit)*

you should write



{letter}({letter}|{digit})*

You also need to move the rules for the function , integer and returns before the rule for the ID, since the rule for the ID matches those too.

+1


source






More articles:


All Articles