idlwave: Breakpoints and Stepping
5.4.3 Breakpoints and Stepping
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IDLWAVE helps you set breakpoints and step through code. Setting a
breakpoint in the current line of the source buffer is accomplished with
‘C-c C-d C-b’ (‘idlwave-shell-break-here’). With a prefix arg of 1
(i.e., ‘C-1 C-c C-d C-b’), the breakpoint gets a ‘/ONCE’ keyword,
meaning that it will be deleted after first use. With a numeric prefix
greater than one (e.g., ‘C-4 C-c C-d C-b’), the breakpoint will only be
active the ‘nth’ time it is hit. With a single non-numeric prefix
(i.e., ‘C-u C-c C-d C-b’), prompt for a condition: an IDL expression to
be evaluated and trigger the breakpoint only if true. To clear the
breakpoint in the current line, use ‘C-c C-d C-d’
(‘idlwave-clear-current-bp’). When executed from the shell window, the
breakpoint where IDL is currently stopped will be deleted. To clear all
breakpoints, use ‘C-c C-d C-a’ (‘idlwave-clear-all-bp’). Breakpoints
can also be disabled and re-enabled: ‘C-c C-d C-\’
(‘idlwave-shell-toggle-enable-current-bp’).
Breakpoint lines are highlighted or indicated with an icon in the
source code (different icons for conditional, after, and other break
types). Disabled breakpoints are _grayed out_ by default. Note that
IDL places breakpoints as close as possible on or after the line you
specify. IDLWAVE queries the shell for the actual breakpoint location
which was set, so the exact line you specify may not be marked. You can
re-sync the breakpoint list and update the display at any time (e.g., if
you add or remove some on the command line) using ‘C-c C-d C-l’.
In recent IDLWAVE versions, the breakpoint line is highlighted when
the mouse is moved over it, and a tooltip pops up describing the break
details. ‘mouse-3’ on the breakpoint line pops up a menu of breakpoint
actions, including clearing, disabling, and adding or changing break
conditions or “after” break count.
Once the program has stopped somewhere, you can step through it. The
most important stepping commands are ‘C-c C-d C-s’ to execute one line
of IDL code ("step into"); ‘C-c C-d C-n’ to step a single line, treating
procedure and function calls as a single step ("step over"); ‘C-c C-d
C-h’ to continue execution to the line at the cursor and ‘C-c C-d C-r’
to continue execution. 
Commands Sent to the Shell, for
information on displaying or hiding the breakpoint and stepping commands
the shell receives. Here is a summary of the breakpoint and stepping
commands:
‘C-c C-d C-b’ Set breakpoint (‘idlwave-shell-break-here’)
‘C-c C-d C-i’ Set breakpoint in module named here
(‘idlwave-shell-break-in’)
‘C-c C-d C-d’ Clear current breakpoint
(‘idlwave-shell-clear-current-bp’)
‘C-c C-d C-a’ Clear all breakpoints (‘idlwave-shell-clear-all-bp’)
‘C-c C-d [’ Go to the previous breakpoint
(‘idlwave-shell-goto-previous-bp’)
‘C-c C-d ]’ Go to the next breakpoint
(‘idlwave-shell-goto-next-bp’)
‘C-c C-d C-\’ Disable/Enable current breakpoint
(‘idlwave-shell-toggle-enable-current-bp’)
‘C-c C-d C-j’ Set a breakpoint at the beginning of the enclosing
routine.
‘C-c C-d C-s’ Step, into function calls (‘idlwave-shell-step’)
‘C-c C-d C-n’ Step, over function calls (‘idlwave-shell-stepover’)
‘C-c C-d C-k’ Skip one statement (‘idlwave-shell-skip’)
‘C-c C-d C-u’ Continue to end of block (‘idlwave-shell-up’)
‘C-c C-d C-m’ Continue to end of function (‘idlwave-shell-return’)
‘C-c C-d C-o’ Continue past end of function (‘idlwave-shell-out’)
‘C-c C-d C-h’ Continue to line at cursor position
(‘idlwave-shell-to-here’)
‘C-c C-d C-r’ Continue execution to next breakpoint, if any
(‘idlwave-shell-cont’)
‘C-c C-d C-up’ Show higher level in calling stack
(‘idlwave-shell-stack-up’)
‘C-c C-d Show lower level in calling stack
C-down’ (‘idlwave-shell-stack-down’)
All of these commands have equivalents in Electric Debug Mode, which
provides faster single-key access (Electric Debug Mode).
The line where IDL is currently stopped, at breakpoints, halts, and
errors, etc., is marked with a color overlay or arrow, depending on the
setting in ‘idlwave-shell-mark-stop-line’. If an overlay face is used
to mark the stop line (as it is by default), when stepping through code,
the face color is temporarily changed to gray, until IDL completes the
next command and moves to the new line.
-- User Option: idlwave-shell-mark-breakpoints (‘t’)
Non-‘nil’ means mark breakpoints in the source file buffers. The
value indicates the preferred method. Valid values are ‘nil’, ‘t’,
‘face’, and ‘glyph’.
-- User Option: idlwave-shell-breakpoint-face
The face for breakpoint lines in the source code if
‘idlwave-shell-mark-breakpoints’ has the value ‘face’.
-- User Option: idlwave-shell-breakpoint-popup-menu (‘t’)
Whether to pop-up a menu and present a tooltip description on
breakpoint lines.
-- User Option: idlwave-shell-mark-stop-line (‘t’)
Non-‘nil’ means mark the source code line where IDL is currently
stopped. The value specifies the preferred method. Valid values
are ‘nil’, ‘t’, ‘arrow’, and ‘face’.
-- User Option: idlwave-shell-overlay-arrow (‘">"’)
The overlay arrow to display at source lines where execution halts,
if configured in ‘idlwave-shell-mark-stop-line’.
-- User Option: idlwave-shell-stop-line-face
The face which highlights the source line where IDL is stopped, if
configured in ‘idlwave-shell-mark-stop-line’.
Info Catalog
idlwave: Debug Key Bindings
idlwave: Debugging IDL Programs
idlwave: Compiling Programs