Fork of fb.debugger: dependency-free

fb.debugger is an excellent debugger for torch and lua in general, and can be found at https://github.com/facebook/fblualib. However, fblualib and its dependencies are quite heavy but you may just want the debugger. This repository is a fork of fb.debugger with dependencies integrated and/or removed.

To run a script and drop into the debugger on an error, simply do:

fbdbg-run script_name.lua your_arg1 your_arg2 ...

Install:

luarocks install https://raw.githubusercontent.com/bshillingford/fbdebugger-minimal/master/fbdebugger-standalone-1.rockspec 

Dependencies:

• penlight >= 1.3.1
• libedit installed in your system (libedit.so anywhere in the library search path).

Original README:

fb-debugger: A source-level Lua debugger

This package implements a source-level Lua debugger.

Usage

You may enter the debugger in two different ways:

• explicitly: at the point of interest, do

local debugger = require('fb.debugger')
debugger.enter()

and you will be dropped in the debugger

• automatically when you hit an (uncaught) error: if using fb.trepl, you may set the environment variable LUA_DEBUG_ON_ERROR to 1, and you'll be dropped in the debugger whenever your code raises an uncaught error.

Debugger commands

help will give you a list of commands, inspired by gdb. The following commands exist and behave similarly to their gdb counterparts:

• help displays help
• where / backtrace / bt displays the current stack trace (with a marker for the currently selected frame)
• frame selects a given frame
• up / down moves the currently selected frame up / down one
• b / break sets a breakpoint at a given location (specified either as <file>:<line_number> or <function_name>; the function name is looked up in the scope of the current frame)
• info breakpoints lists breakpoints
• enable, disable, delete enable, disable, and delete a breakpoint, respectively
• next / n single-steps one line, skipping over function calls
• step / s single-steps one line, descending into function calls
• finish continues execution until the function in the currently selected frame returns
• continue / c continues program execution until the next breakpoint, or until the next time the debugger is reentered (via debugger.enter() or automatically in case of error)
• locals / vlocals shows locals in scope in the current frame; vlocals also shows values (verbose)
• globals / vglobals shows all globals
• upvalues / vupvalues shows the current function's upvalues
• exec / e executes code in the scope of the current frame
• print / p evaluates an expression in the scope of the current frame and prints the result
• list / l lists source code (if available); by default it lists the function in the current frame, but it accepts a location argument just like break; just like gdb, repeating l without arguments continues listing the same file
• quit / q quits the debugger; the program is resumed.

Note that locals, globals, or upvalues will occasionally show a synthetic name for a variable (such as _dbgl_tmp_4). These indicate variables that have been shadowed in the current scope (and so their original name now refers to something else) or internal Lua temporaries (modifying those is ill-advised).