Re: [RFA/doco] Improve doc on how to execute a Python script from GDB.

[Joel Brobecker <brobecker@adacore.com>]

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[ARGH! Resending with the correct version of the patch, this time.
 Sorry about that]

Thanks for the review, Eli.

> > +@item python execfile ("script-name")
> > +This method is based on the @code{execfile} Python built-in function,
> > +and thus is always available.
> 
> "always" as in "when Python is compiled in", right?

That's correct. But since the documentation was inside the section
dedicated to Python support in GDB, I thought I could get away with
not having to conditionalize this with "when Python is compiled in".
I was going to add a small note, but I think we're already covered:
http://www.sourceware.org/gdb/current/onlinedocs/gdb/Python.html#Python

    23.2 Scripting gdb using Python
    
    You can script gdb using the Python programming language. This feature
    is available only if gdb was configured using --with-python. 

So I did not update the current text in this iteration.  Let me know
if I should and I'll send a new patch shortly after.  For your
convenience, I'm sending an extra diff, which shows the changes
from version 1 to version 2. Since the number of changes is small
compared to the size of the patch, it can be hard to spot these changes.

gdb/doc/ChangeLog:

        * gdb.texinfo (File Options): Adjust the documentation of this
        switch to refer to the "source" command rather than partially
        duplicating some of the relevant information.
        (Extending GDB): Introduce and document the set/show script-extension
        setting.
        (Command Files): Add note explaining that the "source" command
        is also used to evalute scripts written in other languages.
        Remove the short slightly incorrect reference to sourcing Python
        scripts.
        (Python Commands): Document how to execute a Python script from GDB.

Ok to checkin?

Thanks,
-- 
Joel

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commit b4561d6f19f96f04be3ad6f5b22ef7750a0c4f40
Author: Joel Brobecker <brobecker@adacore.com>
Date:   Tue Jan 19 18:57:42 2010 +0400

    Improve doc on how to execute a Python script from GDB.
    
    This patch improves on a previous documentation update, which I rebased
    an applied, but turned out to be grossly out of sync with the actual
    code changes.
    
    gdb/doc/ChangeLog:
    
            * gdb.texinfo (File Options): Adjust the documentation of this
            switch to refer to the "source" command rather than partially
            duplicating some of the relevant information.
            (Extending GDB): Introduce and document the set/show script-extension
            setting.
            (Command Files): Add note explaining that the "source" command
            is also used to evalute scripts written in other languages.
    	Remove the short slightly incorrect reference to sourcing Python
            scripts.
            (Python Commands): Document how to execute a Python script from GDB.

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index d716d0d..fbad9fe 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -963,10 +963,8 @@ Connect to process ID @var{number}, as with the @code{attach} command.
 @itemx -x @var{file}
 @cindex @code{--command}
 @cindex @code{-x}
-Execute commands from file @var{file}.  If @var{file} ends in
-@samp{.py}, then the file is evaluated as Python code.  If Python
-support is not enabled in this @value{GDBN}, then the file is assumed to
-contain @value{GDBN} commands, regardless of its extension.
+Execute commands from file @var{file}.  The contents of this file is
+evaluated exactly as the @code{source} command would.
 @xref{Command Files,, Command files}.
 
 @item -eval-command @var{command}
@@ -18907,6 +18905,38 @@ Displays whether the debugger is operating in interactive mode or not.
 on composition of @value{GDBN} commands, and the second is based on the
 Python scripting language.
 
+To facilitate the use of these extensions, @value{GDBN} is capable
+of evaluating the contents of a file.  When doing so, @value{GDBN}
+can recognize which scripting language is being used by looking at
+the filename extension.  Files with an unrecognized filename extension
+are always treated as a @value{GDBN} Command Files.
+@xref{Command Files,, Command files}.
+
+You can control how @value{GDBN} evaluates these files with the following
+setting:
+
+@table @code
+@kindex set script-extension
+@kindex show script-extension
+@item set script-extension off
+All scripts are always evaluated as @value{GDBN} Command Files.
+
+@item set script-extension soft
+The debugger determines the scripting language based on filename
+extension.  If this scripting language is supported, @value{GDBN}
+evaluates the script using that language.  Otherwise, it evaluates
+the file as a @value{GDBN} Command File.
+
+@item set script-extension strict
+The debugger determines the scripting language based on filename
+extension, and evaluates the script using that language.  If the
+language is not supported, then the evaluation fails.
+
+@item show script-extension
+Display the current value of the @code{script-extension} option.
+
+@end table
+
 @menu
 * Sequences::          Canned Sequences of Commands
 * Python::             Scripting @value{GDBN} using Python
@@ -19140,7 +19170,10 @@ does not mean to repeat the last command, as it would from the
 terminal.
 
 You can request the execution of a command file with the @code{source}
-command:
+command.  Note that the @code{source} command is also used to evaluate
+scripts that are not Command Files.  The exact behavior can be configured
+using the @code{script-extension} setting.
+@xref{Extending GDB,, Extending GDB}.
 
 @table @code
 @kindex source
@@ -19162,11 +19195,6 @@ If @code{-v}, for verbose mode, is given then @value{GDBN} displays
 each command as it is executed.  The option must be given before
 @var{filename}, and is interpreted as part of the filename anywhere else.
 
-If @var{filename} ends in @samp{.py}, then @value{GDBN} evaluates the
-contents of the file as Python code.  If Python support is not compiled
-into @value{GDBN}, then the file is assumed to contain @value{GDBN}
-commands, regardless of its extension.
-
 Commands that would ask for confirmation if used interactively proceed
 without asking when used in a command file.  Many @value{GDBN} commands that
 normally print messages to say what they are doing omit the messages
@@ -19444,6 +19472,20 @@ printing is enabled; if @code{off}, then Python stack printing is
 disabled.
 @end table
 
+It is also possible to execute a Python script from the @value{GDBN}
+interpreter:
+
+@table @code
+@item source @file{script-name}
+The script name must end with @samp{.py} and @value{GDBN} must be configured
+to recognize the script language based on filename extension using
+the @code{script-extension} setting.  @xref{Extending GDB, ,Extending GDB}.
+
+@item python execfile ("script-name")
+This method is based on the @code{execfile} Python built-in function,
+and thus is always available.
+@end table
+
 @node Python API
 @subsection Python API
 @cindex python api

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diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 8f31f45..fbad9fe 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -964,7 +964,7 @@ Connect to process ID @var{number}, as with the @code{attach} command.
 @cindex @code{--command}
 @cindex @code{-x}
 Execute commands from file @var{file}.  The contents of this file is
-evaluated exactly as if it was evaluated using the @code{source} command.
+evaluated exactly as the @code{source} command would.
 @xref{Command Files,, Command files}.
 
 @item -eval-command @var{command}
@@ -18907,17 +18907,19 @@ Python scripting language.
 
 To facilitate the use of these extensions, @value{GDBN} is capable
 of evaluating the contents of a file.  When doing so, @value{GDBN}
-can recognize which scripting language is being used by exploiting
+can recognize which scripting language is being used by looking at
 the filename extension.  Files with an unrecognized filename extension
-are always treated as a @value{GDBN} Command Files.  To control how GDB
-evaluates these files, the following setting can be used:
+are always treated as a @value{GDBN} Command Files.
+@xref{Command Files,, Command files}.
+
+You can control how @value{GDBN} evaluates these files with the following
+setting:
 
 @table @code
 @kindex set script-extension
 @kindex show script-extension
 @item set script-extension off
 All scripts are always evaluated as @value{GDBN} Command Files.
-@xref{Command Files,, Command files}.
 
 @item set script-extension soft
 The debugger determines the scripting language based on filename
@@ -19475,7 +19477,7 @@ interpreter:
 
 @table @code
 @item source @file{script-name}
-The script name must end with @samp{.py} and GDB must be configured
+The script name must end with @samp{.py} and @value{GDBN} must be configured
 to recognize the script language based on filename extension using
 the @code{script-extension} setting.  @xref{Extending GDB, ,Extending GDB}.