Interactive Debugger

The Daffodil Command Line Interface (CLI) comes with a built-in interactive debugger that pauses parsing and allows for user inspection current parsing state. Providing the global --debug/-d option drops the user to a prompt, at which point various commands can be entered to control parsing and inspect state. Below are the commands.

Commands

Command

Arguments

Description

Example

break

<element_id>

Create a breakpoint, causing the debugger to stop when the element with the <element_id> name is created

break element.foo

clear

Clear the screen

clear

condition

<breakpoint_id> <dfdl_expression>

Set a condition on a specified breakpoint. When a break point is encountered, the debugger only pauses if the DFDL expression evaluates to true

condition 1 dfdl:occursIndex() = 3

continue

Continue parsing the input data until a breakpoint is encountered. At which point, pause parsing and display a debugger console to the user

continue

delete

<breakpoint_id>

Delete a specified breakpoint.

delete 1

disable

<type> <id>

Disable a specified breakpoint or display. To disable a breakpoint, set <type> to "breakpoint". To disable a display, set <type> to "display".

disable breakpoint 1

disable display 1

display

<debugger command>

Execute a debugger command every time a debugger console is displayed to the user

display info infoset

enable

<type> <id>

Enable a specified breakpoint or display. To enable a breakpoint, set <type> to "breakpoint". To enable a display, set <type> to "display".

enable breakpoint 1

enable display 1

eval

[type] <dfdl_expression>

Evaluate a DFDL expression. The <type> argument determines how to display the result of the dfdl_expression. <type> may be "string", "number", "boolean", or "node". If <type> is not give, then "node" is assumed.

eval number dfdl:occursIndex()

help

[<command>]

Display help. If a command is given, display specific help for that command and its subcommands.

help

help info

info

<item>...

Print various pieces of internal information to the console. The valid items are:

item	description
arrayIndex	current index of the element in an array
bitLimit	current bit limit
bitPosition	current bit position in the data
breakpoints	list of breakpoints
childIndex	current child index
data	input data
descriminator	whether or not a descriminator is set
displays	list of displays
groupIndex	current group index
infoset	current infoset
occursCount	occurs count
path	path in the schema, using schema component designator

info data infoset

set

<setting> <value>

Change a debugger setting. The settings are:

Setting	Type	Description
dataLength	integer	number of bytes to display when displaying input data. If negative, display all input data.
infosetLines	integer	number of lines of the infoset to display. This displays the last X number of lines. If negative, display the entire infoset
removeHidden	boolean	whether or not to remove hidden elements (via dfdl:hiddenGroupRef) when displaying the infoset
wrapLength	integer	number of character at which to wrap data or infoset when printed to the console

set dataLength -1

set wrapLength 50

set removeHidden true

step

Perform a single parse action, pause parsing, and display a debugger console to the user

step

undisplay

<display_id>

Remove a display created using the "display" command

undisplay 1

Space shortcuts

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