accomplished this:
* Lexer and Parser
* Lexer and Parser Generator
* Error Handling
The last part is now working like this:
It uses error recovery to detect more errors, but it always fails at the end. Right now it only recovers from the action ERASE token, however if there are tokens with errors nearby it will stop parsing.
From the papers I read, I have this primary error handling techniques (single correction) which could be insert, replace or erase. So far I have not implemented MERGE because my parser only understand tokens and has no idea about the semantic value of the tokens. I need to implement a table to look for the semantic value, also important for displaying the errors with the right String not with the Token NAME as now.
***ERRORS WERE FOUND AND COULD NOT RECOVER ***
Syntax Error near [TOKEN:T_DO 'do' from (line:3 col:18) until (line:3
col:20)], ERASE token
Syntax Error near [TOKEN:T_ADD '+' from (line:4 col:13) until (line:4
col:14)], INSERT token {T_INTCONST or T_IDENT}
Syntax Error near [TOKEN:T_ADD '+' from (line:4 col:13) until (line:4
col:14)], REPLACE token with {T_LPAREN}
Syntax Error near [TOKEN:T_ADD '+' from (line:4 col:13) until (line:4
col:14)], ERASE token
Syntax Error near [TOKEN:T_IDENT 'y' from (line:8 col:5) until (line:8
col:6)], INSERT token {T_THEN}
program file:
1/* this is while test of comment */
2read x y z w;
3while x <> 99 do do
4 ans := (x++1) - (y/3);
5 write ans;
6 read x, y;
7 if x = 10
8 y := 234;
9 endif
10end My thesis is getting close to the end, I hope it can be completed by the end of this month.
