<>= - - _Lex & Yacc_ ([local copy](lex-yacc.pdf)) - by H. Altay G{\"u}venir - - @ <>=

<></h1> <h2>References</h2> <<references>> Examples All examples below implements the same grammar for the language L={a<sup>n</sup>b<sup>n</sup>|n >= 0}. Standard implementation Standard, non-reentrant implementation: <<listing of anbn0>> Reentrant scanner Reentrant scanner (lexical scanner) using [`flex`](https://github.com/westes/flex): <<listing of anbn1>> Reentrant scanner and parser Reentrant scanner and (pure) parser using `flex` and [`byacc`](https://invisible-island.net/byacc/): <<listing of anbn2>> Reentrant scanner and parser augumented with `noweb` [`icon-rtt`](https://github.com/ctarbide/icon-rtt) do a minimum analysis of the c language sources and translates it to a `noweb` output that removes most of the rigidity of c source code: <<listing of anbn3>> Notes - All code above is provided [here](https://github.com/ctarbide/ctarbide.github.io). - Tested with: - flex 2.6.4 - byacc 2.0 20240109 More details in the link below. @ <<YEAR>>= 2024 @ <<STAMP>>= 2024-06-17_11h27m33 @ <<ITEM_ID>>= anbn_language·cs315·byacc_and_flex·fully_reentrant @ <<ITEM_URI>>= anbn_language%C2%B7cs315%C2%B7byacc_and_flex%C2%B7fully_reentrant @ <<PAGE DIR>>= pages/<<YEAR>>/<<STAMP>>_<<ITEM_ID>> @ <<PAGE URI>>= pages/<<YEAR>>/<<STAMP>>_<<ITEM_URI>> @ <<URL PREFIX>>= <<assets - base url>><<PAGE URI>> @ <<CANONICAL URL>>= <<URL PREFIX>>/index.html @ <<>>= <<sh preamble>> if git-file-is-pristine.sh <<PRIMARY SOURCES>>; then rm -f .draft else date '+%Y-%m-%d_%Hh%Mm%S' > .draft git reset --quiet -- index.html fi nofake --error -Rrender <<PRIMARY SOURCES>> | sh @ <<PRIMARY SOURCES>>= <<TOP>>/assets.nw README.txt @ <<TOP>>= ../../.. @ <<PAGES>>= ../.. @ <<TITLE>>= ctarbi.de - anbn language · reentrant byacc and flex @ <<sh preamble>>= #!/bin/sh set -eu @ <<print LAST MODIFIED>>= if [ -f .draft ]; then last-modified.sh <<PRIMARY SOURCES>> | perl -MPOSIX=strftime \ -lne'print(strftime(qq{@<<LAST MODIFIED@>>=\n%B %e, %Y (DRAFT)\n@\n}, gmtime($_)))' else FORMAT='format:%s %B %e, %Y at %T UTC' git-last-modified.sh <<PRIMARY SOURCES>> | LC_ALL=C sort -nr | head -n1 | perl \ -lne's,^\d+ ,,; print(qq{@<<LAST MODIFIED@>>=\n${_}\n@\n})' fi @ <<set $t0>>= t0=`perl -MTime::HiRes=time -le'print(time)'` @ <<generated: $t1 - $t0>>= perl -MTime::HiRes=time -MPOSIX=strftime -le' $t1 = time; $t0 = $ARGV[0]; printf(qq{\n\n}, $t1 - $t0, strftime(q{%B %e, %Y at %T UTC}, gmtime)) ' -- "${t0}" @ <<create index.html from .index.html>>= cat .index.html > index.html <<generated: $t1 - $t0>> @>> index.html chmod 0444 index.html @ <<update (or not) index.html from .index.html>>= if [ -f index.html ]; then if [ .index.html -nt index.html ]; then rm -f index.html <<create index.html from .index.html>> else echo "index.html is up to date." fi else <<create index.html from .index.html>> fi @ <<gen: base url>>= printf '@<<base url>>=\n' <<TOP>>/bin/show-config.sh website.base-url printf '@\n' @ <<generate>>= <<sh preamble>> <<print LAST MODIFIED>> cat <<PRIMARY SOURCES>> <<gen: base url>> <<gen: listing of anbn0>> <<gen: listing of anbn1>> <<gen: listing of anbn2>> <<gen: listing of anbn3>> @ <<link to ${i}>>= printf -- '- [`%s`](%s)\n\n' "${i}" "${i}" @ <<gen: listing of anbn0>>= printf '@<<listing of anbn0>>=\n' for i in anbn0/; do <<link to ${i}>> done printf '\n@\n' @ <<gen: listing of anbn1>>= printf '@<<listing of anbn1>>=\n' for i in anbn1/; do <<link to ${i}>> done printf '\n@\n' @ <<gen: listing of anbn2>>= printf '@<<listing of anbn2>>=\n' for i in anbn2/; do <<link to ${i}>> done printf '\n@\n' @ <<gen: listing of anbn3>>= printf '@<<listing of anbn3>>=\n' for i in anbn3/*; do <<link to ${i}>> done printf '\n@\n' @ <<update (or not) .index.html from primary sources>>= nofake --error -Rgenerate <<PRIMARY SOURCES>> | sh | gzip > .cache ( gzip -dc .cache printf '@<<body>>=\n' gzip -dc .cache | nofake --error -R'body in markdown' | "<<TOP>>/bin/md-autoheader-autolink.pl" | <<assets - md.pl for pages>> printf '@\n' ) | CHMOD='chmod 0444' nofake.sh --error -Rindex.html -o.index.html @ <<render>>= <<sh preamble>> <<set $t0>> <<update (or not) .index.html from primary sources>> <<update (or not) index.html from .index.html>> @ <<index.html>>= <!DOCTYPE html> <html lang="en"> <title><<TITLE>> <> <