ePerl(3pm) | User Contributed Perl Documentation | ePerl(3pm) |
Parse::ePerl - Perl interface to the ePerl parser
use Parse::ePerl; $rc = Parse::ePerl::Preprocess($p); $rc = Parse::ePerl::Translate($p); $rc = Parse::ePerl::Precompile($p); $rc = Parse::ePerl::Evaluate($p); $rc = Parse::ePerl::Expand($p);
Parse::ePerl is the Perl 5 interface package to the functionality of the ePerl parser (see eperl(1) for more details about the stand-alone program). It directly uses the parser code from ePerl to translate a bristled script into a plain Perl script and additionally provides functions to precompile such scripts into P-code and evaluate those scripts to a buffer.
All functions are parameterized via a hash reference $p which provide the necessary parameters. The result is a return code $rc which indicates success (1) or failure (0).
This is the ePerl preprocessor which expands "#include" directives. See eperl(1) for more details.
Possible parameters for $p:
This is the actual ePerl parser, i.e. this function converts a bristled ePerl-style script (provided in "$p-"{Script}> as a scalar) to a plain Perl script. The resulting script is stored into a buffer provided via a scalar reference in "$p-"{Result}>. The translation is directly done by the original C function Bristled2Plain() from ePerl, so the resulting script is exactly the same as with the stand-alone program eperl.
Possible parameters for $p:
Example: The following code
$script = <<'EOT'; foo <: print "bar"; :> quux EOT Parse::ePerl::Translate({ Script => $script, Result => \$script, });
translates the script in $script to the following plain Perl format:
print "foo\n"; print "bar"; print "\n"; print "quux\n";
This is an optional step between translation and evaluation where the plain Perl script is compiled from ASCII representation to P-code (the internal Perl bytecode). This step is used in rare cases only, for instance from within Apache::ePerl(3) for caching purposes.
Possible parameters for $p:
Example: The following code
Parse::ePerl::Precompile({ Script => $script, Result => \$script, });
translates the plain Perl code (see above) in $script to a code reference and stores the reference again in $script. The code later can be either directly used via &$script instead of "eval($script)" or passed to the Parse::ePerl::Evaluate(3) function.
Beside Parse::ePerl::Translate(3) this is the second main function of this package. It is intended to evaluate the result of Parse::ePerl::Translate(3) in a ePerl-like environment, i.e. this function tries to emulate the runtime environment and behavior of the program eperl. This actually means that it changes the current working directory and evaluates the script while capturing data generated on STDOUT/STDERR.
Possible parameters for $p:
Example: The following code
$script = <<'EOT'; print "foo\n"; print "bar"; print "\n"; print "quux\n"; EOT Parse::ePerl::Evaluate({ Script => $script, Result => \$script, });
translates the script in $script to the following plain data:
foo bar quux
This function just combines, Parse::ePerl::Translate(3) and Parse::ePerl::Evaluate(3) into one step. The parameters in $p are the union of the possible parameters for both functions. This is intended as a high-level interface for Parse::ePerl.
Ralf S. Engelschall rse@engelschall.com www.engelschall.com
Web-References:
Perl: perl(1), http://www.perl.com/ ePerl: eperl(1), http://www.engelschall.com/sw/eperl/
2022-10-20 | perl v5.36.0 |