306 lines
8.5 KiB
C
306 lines
8.5 KiB
C
/*
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* Callisto - standalone scripting platform for Lua 5.4
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* Copyright (c) 2023-2024 Jeremy Baxter.
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*/
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/***
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* Option parsing, and error formatting
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* for the command line.
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* @module cl
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*/
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#include <libgen.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <lua/lauxlib.h>
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#include <lua/lua.h>
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#include "util.h"
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static void
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fmesgshift(lua_State *L, int fd, int shift)
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{
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int paramc, i;
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char *bname;
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char *progname; /* argv[0] */
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lua_getglobal(L, "arg");
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if (!lua_istable(L, -1)) {
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luaL_error(L,
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"arg table not present/inaccessible; cannot get script name");
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return;
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}
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lua_geti(L, -1, 0);
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if (!lua_isstring(L, -1)) {
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luaL_argerror(L, 1, "arg[0] is not a string; cannot print script name");
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return;
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}
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progname = (char *)lua_tostring(L, -1);
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/* format using string.format */
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lua_getglobal(L, "string");
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lua_getfield(L, -1, "format");
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paramc = lua_gettop(L); /* get parameter count */
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for (i = 1 + shift; i <= paramc; i++) { /* for every parameter */
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lua_pushvalue(L, i); /* push argument */
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}
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lua_call(L, paramc - shift, 1);
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bname = basename(progname);
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write(fd, bname, strlen(bname));
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write(fd, ": ", 2);
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write(fd, lua_tostring(L, -1), lua_rawlen(L, -1));
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write(fd, "\n", 1);
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}
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static void
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fmesg(lua_State *L, int fd)
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{
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fmesgshift(L, fd, 0);
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}
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/***
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* Prints a formatted error message to standard error.
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* It looks like so:
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*
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* `progname: message`
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*
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* where *progname* is the name of the current script
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* being executed and *message* is the *message* parameter.
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*
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* The *message* parameter may optionally be followed by
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* a variable number of arguments which are formatted
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* using *string.format*.
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*
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* @function error
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* @usage
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local succeeded, err = io.open("file.txt")
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if not succeeded then
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cl.error("could not open " .. err)
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end
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* @tparam string message The message to print after the program's name. Supports *string.format*-style format specifiers.
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* @param ... Any additional values specified by the format specifiers in the *message* parameter.
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*/
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static int
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cl_error(lua_State *L)
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{
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luaL_checkstring(L, 1);
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fmesg(L, 2);
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return 0;
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}
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/***
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* Prints a formatted message to standard output.
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* It looks like so:
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*
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* `progname: message`
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*
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* where *progname* is the name of the current script
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* being executed and *message* is the (optionally
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* formatted) *message* parameter.
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*
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* The *message* parameter may optionally be followed by
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* a variable number of arguments which are formatted
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* using *string.format*.
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*
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* @function mesg
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* @usage cl.mesg("message to stdout")
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* @tparam string message The message to print after the program's name. Supports *string.format*-style format specifiers.
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* @param ... Any additional values specified by the format specifiers in the *message* parameter.
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*/
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static int
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cl_mesg(lua_State *L)
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{
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luaL_checkstring(L, 1);
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fmesg(L, 1);
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return 0;
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}
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/***
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* Convenience function that calls *cl.error* to
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* print a formatted error message to standard error,
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* then terminates script execution and calls *os.exit*.
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*
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* For more information on the *message* parameter,
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* see the *cl.error* function.
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*
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* @function panic
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* @usage
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local succeeded, err, code = io.open("file.txt")
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if not succeeded then
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-- use a custom exit code:
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cl.panic(code, "could not open " .. err)
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-- use the default exit code (1):
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cl.panic("could not open " .. err)
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end
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* @tparam[opt] integer code The exit code to return to the operating system.
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* @tparam string message The message to print after the program's name. Supports *string.format*-style format specifiers.
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* @param ... Any additional values specified by the format specifiers in the *message* parameter.
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*/
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static int
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cl_panic(lua_State *L)
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{
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int code, codegiven;
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/* get exit code */
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codegiven = lua_isinteger(L, 1);
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code = codegiven ? lua_tointeger(L, 1) : 1;
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/* check arguments */
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luaL_checkstring(L, 1 + codegiven);
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fmesgshift(L, 2, codegiven);
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/* exit */
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lua_close(L);
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if (L) /* used to avoid "unreachable return" warnings */
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exit(code);
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return 0;
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}
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/***
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* Parses the command line argument list *arg*.
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* The string *optstring* may contain the following elements:
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* individual characters, and characters followed by a colon.
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* A character followed by a single colon indicates that an
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* argument is to follow the option on the command line. For
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* example, * an option string `"x"` permits a **-x** option,
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* and an option string `"x:"` permits a **-x** option that
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* must take an argument. An option * string of `"x:yz"` permits
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* a **-x** option that takes an argument, and **-y** and **-z**
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* options, which do not.
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*
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* The function *fn* is run each time a new option of the argument
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* list is processed. It takes the parameters *opt*, *optarg*,
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* *optindex*, and *opterror*.
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* - *opt* is a string containing the option used. It is set
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* to the option the user specified on the command line.
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* If the user specifies an unknown option (one that is
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* not specified in *optstring*), the value of *opt* will
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* be set to nil. If the user specifies an option that
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* requires an argument, but does not specify its argument,
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* the value of *opt* will be the string `"*"` (a single
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* asterisk).
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* - *optarg*, is a string containing the option argument
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* (if applicable).
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* - *optindex* is an integer that contains the index of the
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* last command line argument processed. The last parameter,
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* *opterror*, is set in case of an option error (if *opt*
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* is nil or set to the string `"*"`), and is set to the
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* option that caused an error (in the case of *opt* being
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* nil, this will be the unknown option the user specified,
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* or in the case of *opt* being the string `"*"`, this
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* will be the option that required an argument).
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*
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* @function options
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* @usage
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cl.options(arg, "abc:", function(opt, optarg, optindex, opterror)
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if opt == 'a' then
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print("-a was used")
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elseif opt == 'b' then
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print("-b was used")
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elseif opt == 'c' then
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print("-c was used, with argument " .. optarg)
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elseif opt == '*' then
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print("missing argument for -" .. opterror)
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elseif opt == nil then -- or ``if not opt``
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print("unknown option -" .. opterror)
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end
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end)
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* @tparam table arg The argument table to parse.
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* @tparam string optstring The option string, containing options that should be parsed.
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* @tparam function fn The function to be run each time a new option is specified on the command line.
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*/
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static int
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cl_options(lua_State *L)
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{
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int argc, i;
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char ch, s[2]; /* opt character and string */
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char loptopt[2]; /* opterror, returned to Lua */
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char **argv; /* parameter 1 (table), command line argument vector */
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char *optstring; /* parameter 2 (string), optstring passed to getopt */
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optstring = malloc(lua_rawlen(L, 2) * sizeof(char *));
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/* parameter type checking */
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luaL_checktype(L, 1, LUA_TTABLE);
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strbcpy(optstring, luaL_checkstring(L, 2), lua_rawlen(L, 2) * sizeof(char *));
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luaL_checktype(L, 3, LUA_TFUNCTION);
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argc = (int)lua_rawlen(L, 1) + 1; /* get argv length */
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argv = lua_newuserdatauv(L, (argc + 1) * sizeof(char *), 0);
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argv[argc] = NULL;
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for (i = 0; i < argc; i++) { /* for every argument */
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lua_pushinteger(L, i); /* push argv index */
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lua_gettable(L, 1); /* push argv[i] */
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argv[i] = (char *)luaL_checkstring(L, -1);
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}
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if (optstring[0] == ':')
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return luaL_argerror(L, 2,
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"option string must not start with a colon (:)");
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strprepend(optstring, ":");
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/* getopt loop */
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while ((ch = getopt(argc, argv, optstring)) != -1) {
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/* construct string containing ch */
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s[0] = ch;
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s[1] = 0;
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lua_pushvalue(L, 3);
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/* first function parameter: opt */
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if (ch == '?') /* in case of unknown option */
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lua_pushnil(L);
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else if (ch == ':') /* in case of missing option argument */
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lua_pushliteral(L, "*");
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else /* otherwise just push the option character */
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lua_pushstring(L, s);
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/* second function parameter: optarg */
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lua_pushstring(L, optarg);
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/* third function parameter: optindex */
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lua_pushinteger(L, optind);
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/* fourth function parameter: opterror
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* (only non-nil on error) */
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if (optopt == '?') { /* error was not encountered */
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lua_pushnil(L);
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} else {
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loptopt[0] = optopt;
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loptopt[1] = 0;
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lua_pushstring(L, loptopt);
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}
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lua_pcall(L, 4, 0, 0); /* call Lua function */
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}
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free(optstring);
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return 0;
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}
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/* clang-format off */
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static const luaL_Reg cllib[] = {
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{"mesg", cl_mesg},
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{"error", cl_error},
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{"panic", cl_panic},
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{"options", cl_options},
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{NULL, NULL}
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};
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int
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luaopen_cl(lua_State *L)
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{
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luaL_newlib(L, cllib);
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return 0;
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}
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