Module debug
getting runtime debug information.
Functions
| debug () | Enters an interactive mode with the user, running each string that the user enters. |
| getfenv (o) | Returns the environment of object `o`. |
| gethook (thread) | Returns the current hook settings of the thread, as three values: the current hook function, the current hook mask, and the current hook count (as set by the `debug.sethook` function). |
| getinfo (thread, function, what) | Returns a table with information about a function. |
| getlocal (thread, level, local) | This function returns the name and the value of the local variable with index `local` of the function at level `level` of the stack. |
| getmetatable (object) | Returns the metatable of the given `object` or nil if it does not have a metatable. |
| getregistry () | Returns the registry table (see §3.5). |
| getupvalue (func, up) | This function returns the name and the value of the upvalue with index `up` of the function `func`. |
| setfenv (object, table) | Sets the environment of the given `object` to the given `table`. |
| sethook (thread, hook, mask, count) | Sets the given function as a hook. |
| setlocal (thread, level, local, value) | This function assigns the value `value` to the local variable with index `local` of the function at level `level` of the stack. |
| setmetatable (object, table) | Sets the metatable for the given `object` to the given `table` (which can be nil). |
| setupvalue (func, up, value) | This function assigns the value `value` to the upvalue with index `up` of the function `func`. |
Functions
- debug ()
- Enters an interactive mode with the user, running each string that the user enters. Using simple commands and other debug facilities, the user can inspect global and local variables, change their values, evaluate expressions, and so on. A line containing only the word `cont` finishes this function, so that the caller continues its execution. Note that commands for `debug.debug` are not lexically nested within any function, and so have no direct access to local variables.
- getfenv (o)
-
Returns the environment of object `o`.
Parameters:
- o
- gethook (thread)
-
Returns the current hook settings of the thread, as three values: the
current hook function, the current hook mask, and the current hook count
(as set by the `debug.sethook` function).
Parameters:
- thread
- getinfo (thread, function, what)
-
Returns a table with information about a function. You can give the
function directly, or you can give a number as the value of `function`,
which means the function running at level `function` of the call stack
of the given thread: level 0 is the current function (`getinfo` itself);
level 1 is the function that called `getinfo`; and so on. If `function`
is a number larger than the number of active functions, then `getinfo`
returns nil.
`thread` and `what` are optional.
The returned table can contain all the fields returned by `lua_getinfo`,
with the string `what` describing which fields to fill in. The default for
`what` is to get all information available, except the table of valid
lines. If present, the option '`f`' adds a field named `func` with
the function itself. If present, the option '`L`' adds a field named
`activelines` with the table of valid lines.
For instance, the expression `debug.getinfo(1,"n").name` returns a table
with a name for the current function, if a reasonable name can be found,
and the expression `debug.getinfo(print)` returns a table with all available
information about the `print` function.
Parameters:
- thread
- function
- what
- getlocal (thread, level, local)
-
This function returns the name and the value of the local variable with
index `local` of the function at level `level` of the stack. (The first
parameter or local variable has index 1, and so on, until the last active
local variable.) The function returns nil if there is no local variable
with the given index, and raises an error when called with a `level` out
of range. (You can call `debug.getinfo` to check whether the level is valid.)
Variable names starting with '`(`' (open parentheses) represent internal
variables (loop control variables, temporaries, and C function locals).
Parameters:
- thread
- level
- local
- getmetatable (object)
-
Returns the metatable of the given `object` or nil if it does not have
a metatable.
Parameters:
- object
- getregistry ()
- Returns the registry table (see §3.5).
- getupvalue (func, up)
-
This function returns the name and the value of the upvalue with index
`up` of the function `func`. The function returns nil if there is no
upvalue with the given index.
Parameters:
- func
- up
- setfenv (object, table)
-
Sets the environment of the given `object` to the given `table`. Returns
`object`.
Parameters:
- object
- table
- sethook (thread, hook, mask, count)
-
Sets the given function as a hook. The string `mask` and the number
`count` describe when the hook will be called. The string mask may have
the following characters, with the given meaning:
* `"c"`: the hook is called every time Lua calls a function;
* `"r"`: the hook is called every time Lua returns from a function;
* `"l"`: the hook is called every time Lua enters a new line of code.
With a `count` different from zero, the hook is called after every `count`
instructions.
When called without arguments, `debug.sethook` turns off the hook.
When the hook is called, its first parameter is a string describing
the event that has triggered its call: `"call"`, `"return"` (or `"tail
return"`, when simulating a return from a tail call), `"line"`, and
`"count"`. For line events, the hook also gets the new line number as its
second parameter. Inside a hook, you can call `getinfo` with level 2 to
get more information about the running function (level 0 is the `getinfo`
function, and level 1 is the hook function), unless the event is `"tail
return"`. In this case, Lua is only simulating the return, and a call to
`getinfo` will return invalid data.
Parameters:
- thread
- hook
- mask
- count
- setlocal (thread, level, local, value)
-
This function assigns the value `value` to the local variable with
index `local` of the function at level `level` of the stack. The function
returns nil if there is no local variable with the given index, and raises
an error when called with a `level` out of range. (You can call `getinfo`
to check whether the level is valid.) Otherwise, it returns the name of
the local variable.
Parameters:
- thread
- level
- local
- value
- setmetatable (object, table)
-
Sets the metatable for the given `object` to the given `table` (which
can be nil).
Parameters:
- object
- table
- setupvalue (func, up, value)
-
This function assigns the value `value` to the upvalue with index `up`
of the function `func`. The function returns nil if there is no upvalue
with the given index. Otherwise, it returns the name of the upvalue.
Parameters:
- func
- up
- value