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usr
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share
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doc
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perl-Parse-RecDescent-1.967009
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demo
#!/usr/bin/perl -ws # THE COMMONEST REASON FOR WANTING LEFT RECURSION use strict; use Parse::RecDescent; $::RD_HINT = 1; sub Parse::RecDescent::evalop { $_[0][0] = $_[0][$_+1](@{$_[0]}[0,$_+2]) for map 2*($_-1), 1..@{$_[0]}/2; return $_[0][0]; } my $parse = Parse::RecDescent->new(<<'EndGrammar'); main: expr /\Z/ { $item[1] } | <error> expr: <leftop:term add_op term> { evalop($item[1]) } add_op: '+' { sub { $_[0] += $_[1] } } | '-' { sub { $_[0] -= $_[1] } } term: <leftop:factor mult_op factor> { evalop($item[1]) } mult_op: '*' { sub { $_[0] *= $_[1] } } | '/' { sub { $_[0] /= $_[1] } } factor: number | '(' expr ')' { $item[2] } number: /[-+]?\d+(\.\d+)?/ EndGrammar while (<DATA>) { print "$_ = ", $parse->main($_), "\n"; } while (print "> " and defined($_=<>)) { print "= ", $parse->main($_), "\n"; } __DATA__ 2+3 2*3 +1-1+1-1+1-1+1-1+1 7*7-6*8 121/(121/11)/121*11 1/(10-1/(1/(10-1)))
[-] demo_cpp.pl
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[-] demo_autorule.pl
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[-] demo_errors.pl
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[-] demo_piecewise.pl
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[-] demo_logic.pl
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[-] demo_skipcomment.pl
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[-] demo_implicit.pl
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[-] demo_separators.pl
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[-] demo_perlparsing.pl
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[-] demo_street.pl
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[-] demo_scoredsep.pl
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[-] demo.c
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[-] demo_textgen.pl
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[-] demo.pl
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[-] demo_calc.pl
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[+]
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[-] demo_another_Cgrammar.pl
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[-] demo_matchrule2.pl
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[-] demo_mccoy.pl
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[-] demo_restructure_painful.pl
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[-] demo_methods.pl
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[-] demo_language.pl
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[-] demo_selfmod.pl
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[-] demo_OOautoparsetree.pl
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[-] demo_codeblock.pl
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[-] demo_simplequery.pl
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[-] demo_restructure_easy.pl
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[-] demo_tokens.pl
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[-] demo_decomment.pl
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[-] demo_recipe.pl
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[-] demo_delete.pl
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[-] demo_lisplike.pl
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[-] demo_bad.pl
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[-] demo_arithmetic.pl
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[-] demo_leftassoc.pl
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[-] demo_PerlCSV.pl
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[-] demo_metaRD.pm
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[-] demo_derived.pl
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[-] demo_opreps.pl
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[-] demo_matchrule.pl
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[-] demo_LaTeXish_autoact.pl
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[-] demo_operator.pl
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[-] demo_autoscoresep.pl
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[-] demo_Cgrammar_v2.pl
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[-] demo_NL2SQL.pl
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[-] demo_Cgrammar.pl
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[-] demo_randomsentence.pl
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[-] demo_template.pl
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[-] demo_quicklist.pl
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[-] demo_itemhash.pl
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[-] demo_buildcalc.pl
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[-] demo_leftop.pl
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[-] demo_decomment_nonlocal.pl
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[-] demo_dot.pl
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[-] demo_LaTeXish.pl
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[-] demo_precalc.pl
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[-] demo_eval.pl
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[-] demo_autostub.pl
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[-] demo_whoson.pl
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[-] demo_lexer.pl
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[-] demo_OOparsetree.pl
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[-] demo_parsetree.pl
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[-] demo_simple.pl
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[-] demo_embedding.pl
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[-] demo_simpleXML.pl
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[-] demo_undumper.pl
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