Command evaluation and cracking. More...

#include "config.h"
#include "constants.h"
#include "typedefs.h"
#include "macros.h"
#include "externs.h"
#include "prototypes.h"
#include <stdbool.h>
#include <ctype.h>
#include <string.h>

Include dependency graph for eval.c:

Classes
struct	tcache_ent

Typedefs
typedef struct tcache_ent	TCENT

Functions
char *	parse_to_cleanup (int eval, bool first, char cstr, char rstr, char *zstr)
	Helper for parse_to. More...

char *	parse_to (char **dstr, char delim, int eval)
	Split a line at a character, obeying nesting. More...

char *	parse_arglist (dbref player, dbref caller, dbref cause, char dstr, char delim, dbref eval, char fargs[], dbref nfargs, char *cargs[], dbref ncargs)
	Parse a line into an argument list contained in lbufs. More...

int	get_gender (dbref player)
	Process a command line, evaluating function calls and %-substitutions. More...

void	tcache_init (void)
	Initialize trace cache. More...

int	tcache_empty (void)
	Empty trace cache. More...

void	tcache_add (char orig, char result)
	Add to the trace cache. More...

void	tcache_finish (dbref player)
	Terminate trace cache. More...

bool	special_char (unsigned char ch)
	Check if character is a special char. More...

bool	token_char (int ch)
	Check if a character is a token. More...

char *	get_subj (int subj)
	Get subject pronoun. More...

char *	get_poss (int poss)
	Get Possessive Adjective pronoun. More...

char *	get_obj (int obj)
	Get Object pronoun. More...

char *	get_absp (int absp)
	Get Absolute Possessive pronoun. More...

void	exec (char buff, char bufc, dbref player, dbref caller, dbref cause, int eval, char dstr, char cargs[], int ncargs)
	Execute commands. More...

GDATA *	save_global_regs (const char *funcname)
	Save the global registers to protect them from various sorts of munging. More...

void	restore_global_regs (const char funcname, GDATA preserve)
	Restore the global registers to protect them from various sorts of munging. More...

Variables
struct tcache_ent *	tcache_head

int	tcache_top

int	tcache_count

Detailed Description

Command evaluation and cracking.

Author: TinyMUSH development team (https://github.com/TinyMUSH)

Version: 3.3

Date: 2020-12-28

Copyright: Copyright (C) 1989-2021 TinyMUSH development team. You may distribute under the terms the Artistic License, as specified in the COPYING file.

Function Documentation

◆ exec()

void exec	(	char *	buff,
		char **	bufc,
		dbref	player,
		dbref	caller,
		dbref	cause,
		int	eval,
		char **	dstr,
		char *	cargs[],
		int	ncargs
	)

Execute commands.

Parameters

buff	Output buffer
bufc	Output buffer tracker
player	DBref of player
caller	DBref of caller
cause	DBref of cause
eval	Evaluation flags
dstr	Destination Buffer
cargs	Command arguments
ncargs	Number of command arguments

Extend the buffer if we need to.

If we are tracing, save a copy of the starting buffer

Mundane characters are the most common. There are usually a bunch in a row. We should just copy them.

We must have a special character at this point.

A space. Add a space if not compressing or if previous char was not a space

General escape. Add the following char without special processing

Function start. Evaluate the contents of the square brackets as a function. If no closing bracket, insert the [ and continue.

Literal start. Insert everything up to the terminating } without parsing. If no closing brace, insert the { and continue.

Preserve leading spaces (Felan)

Percent-replace start. Evaluate the chars following and perform the appropriate substitution.

Null - all done

Command argument number N

Carriage return

Tab

Blank

c is last command executed

c is color

ANSI color

Note: There is an interesting bug/misfeature in the implementation of v? and q? – if the second character is garbage or non-existent, it and the leading v or q gets eaten. In the interests of not changing the old behavior, this is not getting "fixed", but in this case, where moving the pointer back without exiting on an error condition ends up turning things black, the behavior must by necessity be different. So we do break out of the switch.

just skip over the characters

Xterm colors

Todo:: Fix bugs and streamline implementation

We are dealing with background

We are dealing with foreground

Ok we got a color to process

Ran off the end. Back up.

Now we have the color string... Time to handle it

Shall we continue?

Equivalent of generic v() attr get

Ran off the end. Back up.

x-variable

Check for _<varname>

Copy. No interpretation.

We ran off the end of the string without finding a termination condition. Go back.

Variable attribute

Local registers

We know there's no result, so we just advance past.

Whoops, no end. Go back.

Ran off the end. Back up.

Objective pronoun

Personal pronoun

Subjective pronoun

Absolute possessive - idea from Empedocles

Invoker DB number

Executor DB number

Invoker name

Invoker location db#

Caller dbref

Enactor's objID

itext() equivalent

itext2() equivalent

use absolute level number

use number as delta back from current

Arguments to function

Piped command output

Percent - a literal %

Just copy

Arglist start. See if what precedes is a function. If so, execute it if we should.

Load an sbuf with an uppercase version of the func name, and see if the func exists. Trim trailing spaces from the name if configured.

If not a builtin func, check for global func

Do the right thing if it doesn't exist

If no closing delim, just insert the '(' and continue normally

Count number of args returned

We've got function(args) now, so back up over function name in output buffer.

If it's a user-defined function, perform it now.

Return the space allocated for the args

If the number of args is right, perform the func. Otherwise return an error message. Note that parse_arglist returns zero args as one null arg, so we have to handle that case specially.

Check recursion limit

Deal with the peculiar case of the calling object being destroyed mid-function sequence, such as with a command()/@destroy combo...

Return the space allocated for the arguments

We should never reach this point unless we're in a loop or switch, thanks to the table lookup.

Nesting level of loop takes precedence over switch nesting level.

If we're eating spaces, and the last thing was a space, eat it up. Complicated by the fact that at_space is initially true. So check to see if we actually put something in the buffer, too.

The ansi() function knows how to take care of itself. However, if the player used a x sub in the string, and hasn't yet terminated the color with a xn yet, we'll have to do it for them.

Report trace information

◆ get_absp()

char * get_absp ( int absp )

Get Absolute Possessive pronoun.

Parameters

subj	id of the pronoun

Returns: char*

◆ get_gender()

int get_gender ( dbref player )

Process a command line, evaluating function calls and %-substitutions.

Parameters

player DBref of player

Returns: int

◆ get_obj()

char * get_obj ( int obj )

Get Object pronoun.

Parameters

subj	id of the pronoun

Returns: char*

◆ get_poss()

char * get_poss ( int poss )

Get Possessive Adjective pronoun.

Parameters

subj	id of the pronoun

Returns: char*

◆ get_subj()

char * get_subj ( int subj )

Get subject pronoun.

Parameters

subj	id of the pronoun

Returns: char* pronoun

◆ parse_arglist()

char * parse_arglist	(	dbref	player,
		dbref	caller,
		dbref	cause,
		char *	dstr,
		char	delim,
		dbref	eval,
		char *	fargs[],
		dbref	nfargs,
		char *	cargs[],
		dbref	ncargs
	)

Parse a line into an argument list contained in lbufs.

A pointer is returned to whatever follows the final delimiter. If the arglist is unterminated, a NULL is returned. The original arglist is destructively modified.

Parameters

player	DBref of player
caller	DBref of caller
cause	DBref of cause
dstr	Destination buffer
delim	Delimiter
eval	DBref of victim
fargs	Function arguments
nfargs	Number of function arguments
cargs	Command arguments
ncargs	Niimber of command arguments

Returns: char*

◆ parse_to()

char * parse_to	(	char **	dstr,
		char	delim,
		int	eval
	)

Split a line at a character, obeying nesting.

The line is destructively modified (a null is inserted where the delimiter was found) dstr is modified to point to the char after the delimiter, and the function return value points to the found string (space compressed if specified). If we ran off the end of the string without finding the delimiter, dstr is returned as NULL.

Parameters

dstr	String to parse
delim	Delimiter
eval	Evaluation flags

Returns: char*

general escape

also escapes chars

If we hit something on the stack, unwind to it Otherwise (it's not on stack), if it's our delim we are done, and we convert the delim to a null and return a ptr to the char after the null. If it's not our delimiter, skip over it normally

space

◆ parse_to_cleanup()

char * parse_to_cleanup	(	int	eval,
		bool	first,
		char *	cstr,
		char *	rstr,
		char *	zstr
	)

Helper for parse_to.

Parameters

eval	Evaluation flags
first	Is this the first pass?
cstr	String buffer
rstr	String buffer
zstr	String buffer

Returns: char*

◆ restore_global_regs()

void restore_global_regs	(	const char *	funcname,
		GDATA *	preserve
	)

Restore the global registers to protect them from various sorts of munging.

Parameters

funcname	Function name
preserve	Buffer where globals have been saved to.

No change in the values. Move along.

Rather than doing a big free-and-copy thing, we could just handle changes in the data structure size. Place for future optimization.

◆ save_global_regs()

GDATA * save_global_regs ( const char * funcname )

Save the global registers to protect them from various sorts of munging.

Parameters

funcname Function name

Returns: GDATA*

◆ special_char()

bool special_char ( unsigned char ch )

Check if character is a special char.

ASCII table for reference

0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F

0 NUL SOH STX ETX EOT ENQ ACK BEL BS TAB LF VT FF CR SO SI 1 DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US 2 SPC ! " # $ % & ' ( ) * + , - . / 3 0 1 2 3 4 5 6 7 8 9 : ; < = > ? 4 @ A B C D E F G H I J K L M N O 5 P Q R S T U V W X Y Z [ \ ] ^ _ 6 ` a b c d e f g h i j k l m n o 7 p q r s t u v w x y z { | } ~ DEL

We want '', ESC, ' ', '\', '[', '{', '(', '', and '#'.

Parameters

ch	Character to check

Returns: bool True if special, false if not.

We adjust the return value in order to avoid always treating '#' like a special character, as it gets used a whole heck of a lot.

◆ tcache_add()

void tcache_add	(	char *	orig,
		char *	result
	)

Add to the trace cache.

Parameters

orig	Origin buffer
result	Result buffer

◆ tcache_empty()

int tcache_empty ( void )

Empty trace cache.

Returns: int

◆ tcache_finish()

void tcache_finish ( dbref player )

Terminate trace cache.

Parameters

player DBref of player

Ick. If we have no pointer, we should have no flag.

◆ tcache_init()

void tcache_init ( void )

Initialize trace cache.

◆ token_char()

bool token_char ( int ch )

Check if a character is a token.

We want '!', '#', '$', '+', 'A'.

Parameters

ch	Character to check

Returns: char 1 if true, 0 if false

Classes

Typedefs

Functions

Variables

Detailed Description

Function Documentation

◆ exec()

◆ get_absp()

◆ get_gender()

◆ get_obj()

◆ get_poss()

◆ get_subj()

◆ parse_arglist()

◆ parse_to()

◆ parse_to_cleanup()

◆ restore_global_regs()

◆ save_global_regs()

◆ special_char()

◆ tcache_add()

◆ tcache_empty()

◆ tcache_finish()

◆ tcache_init()

◆ token_char()