Hi Bernd,
In your one screeners section you list Rodriguez's BNF parcer generator
slightly modified to run on bigforth. I am trying to use it to recognize
binary strings. The task is to leave 0s and 1s on stack given single
continuous string of 0s and 1s. It does not quite work.
In my code, below, please note the change in the second line from *0
Variable success* to *0 Variable success success !* It seems to be
correct that way.
<eol> does not make sense to me since I am not sure how bigforth
signifies end of line in tib.
I will appreciate your usage example that does work on bigforth. Of
course, if you have ever tested in on bigforth.
Thanks!
--
Sergey
Here is the complete file listing:
\ BNF Parser (c) 1988 B. J. Rodriguez
0 Variable success success ! \ instead of 0 Variable success
: <bnf ( -- ) success @ IF r> >in @ >r dp @ >r >r
ELSE r> drop THEN ;
: bnf> ( -- ) success @ IF r> r> r> 2drop >r
ELSE r> r> dp ! r> >in ! >r THEN ;
: || ( -- ) success @ IF r> r> r> 2drop drop
ELSE r> r> r> 2dup >r >r >in ! dp ! 1 success ! >r THEN ;
: bnf: ( -- sys ) : postpone recursive postpone <bnf ; immediate
: ;bnf ( sys -- ) postpone bnf> postpone ; ; immediate
: @token ( -- n ) source >in @ /string drop c@ ;
: +token ( f -- ) IF 1 >in +! THEN ;
: =token ( n -- ) success @ IF @token = dup success ! +token
ELSE drop THEN ;
: token ( n -- ) Create c, DOES> ( a -- ) c@ =token ;
hex '0 token '0' '1 token '1' 0 token <EOL>
bnf: {binary} '0' || '1' ;bnf
bnf: <binary> @token {binary} dup '0 = if 0 swap then '1 = if 1 then ;bnf
bnf: <number> <binary> <number> || <binary> ;bnf
: mparse
true SUCCESS ! <number> <eol>
cr success @ if ." Successful" else ." Failed" then ;
decimal
mparse 101010
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