treereg(1) · macOS Kılavuz Sayfası

Synopsis

	 treereg [-m packagename] [[no]syntax] [[no]numbers] [-severity 0|1|2|3] \
		 [-p treeprefix] [-o outputfile] [-lib /path/to/library/] -i filename[.trg]
	 treereg [-m packagename] [[no]syntax] [[no]numbers] [-severity 0|1|2|3] \
		 [-p treeprefix] [-lib /path/to/library/] [-o outputfile] filename[.trg]
	 treereg -v
	 treereg -h

Options

Options can be used both with one dash and double dash. It is not necessary to write the full name of the option. A disambiguation prefix suffices.

• "-i[n] filename"

Input file. Extension ".trg" is assumed if no extension is provided.

• "-o[ut] filename"

Output file. By default is the name of the input file (concatenated with .pm)

• "-m[od] packagename"

Name of the package containing the generated subroutines. By default is the longest prefix of the input file name that conforms to the classic definition of integer "[a-z_A-Z]\w*".

• "-l[ib] /path/to/library/"

Specifies that "/path/to/library/" will be included in @INC. Useful when the "syntax" option is on. Can be inserted as many times as necessary.

• "-p[refix] treeprefix"

Tree nodes automatically generated using "Parse::Eyapp" are objects blessed into the name of the production. To avoid crashes the programmer may prefix the class names with a given prefix when calling the parser; for example:

$self->YYParse( yylex => &_Lexer, yyerror => &_Error, yyprefix => PACKAGE."::")

The "-prefix treeprefix" option simplifies the process of writing the tree grammar so that instead of writing with the full names

CLASS::TIMES(CLASS::NUM, $x) and { $NUM->{VAL} == 0) => { $NUM }

it can be written:

TIMES(NUM, $x) and { $NUM->{VAL} == 0) => { $NUM }

• "-n[umbers]"

Produces "#line" directives.

• "-non[umbers]"

Disable source file line numbering embedded in your parser

• "-sy[ntax]"

Checks that Perl code is syntactically correct.

• "-nosy[ntax]"

Does not check the syntax of Perl code

• "-se[verity] number"

0 = Don't check arity (default). Matching does not check the arity. The actual node being visited may have more children.
1 = Check arity. Matching requires the equality of the number of children and the actual node and the pattern.
2 = Check arity and give a warning
3 = Check arity, give a warning and exit • "-v[ersion]"

Gives the version

• "-u[sage]"

Prints the usage info

• "-h[elp]"

Print this help

Description

"Treereg" translates a tree grammar specification file (default extension ".trg" describing a set of tree patterns and the actions to modify them using tree-terms like:

TIMES(NUM, $x) and { $NUM->{VAL} == 0) => { $NUM }

which says that wherever an abstract syntax tree representing the product of a numeric expression with value 0 times any other kind of expression, the "TIMES" tree can be substituted by its left child.

The compiler produces a Perl module containing the subroutines implementing those sets of pattern-actions.

Example

Consider the following "eyapp" grammar (see the "Parse::Eyapp" documentation to know more about "Parse::Eyapp" grammars):

nereida:~/LEyapp/examples> cat Rule6.yp %{ use Data::Dumper; %} %right '=' %left '-' '+' %left '*' '/' %left NEG %tree

%% line: exp { $_[1] } ;

exp: %name NUM NUM | %name VAR VAR | %name ASSIGN VAR '=' exp | %name PLUS exp '+' exp | %name MINUS exp '-' exp | %name TIMES exp '' exp | %name DIV exp '/' exp | %name UMINUS '-' exp %prec NEG | '(' exp ')' { $_[2] } / Let us simplify a bit the tree */ ;

sub _Error { die "Syntax error.\n"; }

sub _Lexer { my($parser)=shift;

$parser->YYData->{INPUT} or $parser->YYData->{INPUT} = or return('',undef);

$parser->YYData->{INPUT}=~s/^\s+//;

for ($parser->YYData->{INPUT}) { s/^([0-9]+(?:.[0-9]+)?)// and return('NUM',$1); s/^([A-Za-z][A-Za-z0-9_]*)// and return('VAR',$1); s/^(.)//s and return($1,$1); } }

sub Run { my($self)=shift; $self->YYParse( yylex => &_Lexer, yyerror => &_Error ); }

Compile it using "eyapp":

nereida:/LEyapp/examples> eyapp Rule6.yp nereida:/LEyapp/examples> ls -ltr | tail -1 -rw-rw---- 1 pl users 4976 2006-09-15 19:56 Rule6.pm

Now consider this tree grammar:

nereida:~/LEyapp/examples> cat Transform2.trg %{ my %Op = (PLUS=>'+', MINUS => '-', TIMES=>'*', DIV => '/'); %}

fold: 'TIMES|PLUS|DIV|MINUS':bin(NUM($n), NUM($m)) => { my $op = $Op{ref($bin)}; $n->{attr} = eval "$n->{attr} $op $m->{attr}"; $[0] = $NUM[0]; } zero_times_whatever: TIMES(NUM($x), .) and { $x->{attr} == 0 } => { $[0] = $NUM } whatever_times_zero: TIMES(., NUM($x)) and { $x->{attr} == 0 } => { $_[0] = $NUM }

Compile it with "treereg":

nereida:/LEyapp/examples> treereg Transform2.trg nereida:/LEyapp/examples> ls -ltr | tail -1 -rw-rw---- 1 pl users 1948 2006-09-15 19:57 Transform2.pm

The following program makes use of both modules "Rule6.pm" and "Transform2.pm":

nereida:~/LEyapp/examples> cat foldand0rule6_3.pl #!/usr/bin/perl -w use strict; use Rule6; use Parse::Eyapp::YATW; use Data::Dumper; use Transform2;

$Data::Dumper::Indent = 1; my $parser = new Rule6(); my $t = $parser->Run; print "\n* Before \n"; print Dumper($t); $t->s(@Transform2::all); print "\n* After ****\n"; print Dumper($t);

When the program runs with input "b*(2-2)" produces the following output:

nereida:~/LEyapp/examples> foldand0rule6_3.pl b*(2-2)

***** Before ****** $VAR1 = bless( { 'children' => [ bless( { 'children' => [ bless( { 'children' => [], 'attr' => 'b', 'token' => 'VAR' }, 'TERMINAL' ) ] }, 'VAR' ), bless( { 'children' => [ bless( { 'children' => [ bless( { 'children' => [], 'attr' => '2', 'token' => 'NUM' }, 'TERMINAL' ) ] }, 'NUM' ), bless( { 'children' => [ bless( { 'children' => [], 'attr' => '2', 'token' => 'NUM' }, 'TERMINAL' ) ] }, 'NUM' ) ] }, 'MINUS' ) ] }, 'TIMES' );

* After ** $VAR1 = bless( { 'children' => [ bless( { 'children' => [], 'attr' => 0, 'token' => 'NUM' }, 'TERMINAL' ) ] }, 'NUM' );

See also the section "Compiling: More Options" in Parse::Eyapp for a more contrived example.

Author

Casiano Rodriguez-Leon

License And Copyright

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.8 or, at your option, any later version of Perl 5 you may have available.

Pod Errors

Hey! The above document had some coding errors, which are explained below:

perl v5.34.0 2017-06-14 TREEREG(1)

treereg