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.\" ========================================================================
.\"
.IX Title "PSHDEVEL 1"
.TH PSHDEVEL 1 "2003-01-02" "perl v5.8.0" "User Contributed Perl Documentation"
.SH "NAME"
psh \- Developing for Perl Shell
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
Developing for the Perl Shell.
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
.Sh "\s-1DEBUGGING\s0"
.IX Subsection "DEBUGGING"
The \fB\-d\fR option puts \fBpsh\fR into \*(L"debugging\*(R" mode, which prints
diagnostic output. Note that you can also enter/leave this
debugging mode in a running \fBpsh\fR via the \f(CW$Psh::debugging\fR variable.
.PP
Possible values for \fB\-d\fR/\f(CW$Psh::debugging\fR are either 0 to disable
it, 1 to enable all debug messages or a string of characters where
each character denotes a certain class of debug messages.
.ie n .IP """s"" \- enables printing of information about the chosen strategy for each command" 4
.el .IP "\f(CWs\fR \- enables printing of information about the chosen strategy for each command" 4
.IX Item "s - enables printing of information about the chosen strategy for each command"
.PD 0
.ie n .IP """o"" \- enables printing of ""other"" debug info \- info which has not been further categorized" 4
.el .IP "\f(CWo\fR \- enables printing of ``other'' debug info \- info which has not been further categorized" 4
.IX Item "o - enables printing of other debug info - info which has not been further categorized"
.ie n .IP """f"" \- enables printing of the rc files read by psh on startup while it is executed and allows easy tracing of problems in these files" 4
.el .IP "\f(CWf\fR \- enables printing of the rc files read by psh on startup while it is executed and allows easy tracing of problems in these files" 4
.IX Item "f - enables printing of the rc files read by psh on startup while it is executed and allows easy tracing of problems in these files"
.ie n .IP """i"" \- enables printing of initialization debug info" 4
.el .IP "\f(CWi\fR \- enables printing of initialization debug info" 4
.IX Item "i - enables printing of initialization debug info"
.ie n .IP """e"" \- enables printing of otherwise suppressed error messages" 4
.el .IP "\f(CWe\fR \- enables printing of otherwise suppressed error messages" 4
.IX Item "e - enables printing of otherwise suppressed error messages"
.ie n .IP """c"" \- enables printing of debug messages for completion" 4
.el .IP "\f(CWc\fR \- enables printing of debug messages for completion" 4
.IX Item "c - enables printing of debug messages for completion"
.PD
.Sh "\s-1SPEED\s0"
.IX Subsection "SPEED"
Even though \fBpsh\fR aims to be an interactive shell instead of a scripting
environment, speed is important. The main concern here is that startup
speed of \fBpsh\fR, which is primarily determined by two factors:
.IP "perl startup and module loading" 4
.IX Item "perl startup and module loading"
.PD 0
.IP "command processing speed" 4
.IX Item "command processing speed"
.PD
.PP
The startup time on a normal, not to busy, computer should be smaller than
one second. To make this possible, keep some simple rules in mind:
.ie n .IP "prefer ""require""\fR to \f(CW""use"" whenever possible" 4
.el .IP "prefer \f(CWrequire\fR to \f(CWuse\fR whenever possible" 4
.IX Item "prefer require to use whenever possible"
.PD 0
.IP "delay loading modules until they are really needed" 4
.IX Item "delay loading modules until they are really needed"
.ie n .IP "let the ""applies"" method of evaluation strategies be as fast as possible" 4
.el .IP "let the \f(CWapplies\fR method of evaluation strategies be as fast as possible" 4
.IX Item "let the applies method of evaluation strategies be as fast as possible"
.PD
.Sh "BUILT-IN \s-1FUNCTIONS\s0"
.IX Subsection "BUILT-IN FUNCTIONS"
On startup, \f(CW\*(C`psh\*(C'\fR scans the Psh::Builtins:: namespace and will add
the names of all found dynamic loadable builtins to \f(CW%Psh::built_ins\fR.
.PP
During evaluation of an input line, \f(CW\*(C`psh\*(C'\fR will first check the
\&\f(CW%Psh::built_ins\fR variable. If this fails it will try to locate an
appropriate built-in function in Psh::Builtins.pm.
.PP
A dynamical loadable builtin has to be in a file called Builtinname.pm
within the Psh::Builtins:: namespace and has at least one subroutine, called
\&'bi_builtinname'. Additionally, it may provide a cmpl_builtinname
subroutine for a custom completion. Furthermore, a builtin should
contain some pod documentation, starting with \*(L"=item * \*(R" and ending
with \*(L"=cut\*(R". The builtin will be called with 2 arguments, the first
one if the rest of the line while the second one is an array to
all the words psh discovered.
.PP
For a list of the predefined \fBpsh\fR builtins, use the \*(L"help\*(R" command from within \fBpsh\fR.
.Sh "\s-1DEFINING\s0 \s-1EVALUATION\s0 \s-1STRATEGIES\s0"
.IX Subsection "DEFINING EVALUATION STRATEGIES"
Currently empty due to overhaul of strategies
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright (C) 1999\-2003 Gregor N. Purdy. All rights reserved.
This script is free software. It may be copied or modified according
to the same terms as Perl itself.