433 lines
12 KiB
C
433 lines
12 KiB
C
/*******************************************************************
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** f i c l . c
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** Forth Inspired Command Language - external interface
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** Author: John Sadler (john_sadler@alum.mit.edu)
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** Created: 19 July 1997
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**
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*******************************************************************/
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/*
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** This is an ANS Forth interpreter written in C.
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** Ficl uses Forth syntax for its commands, but turns the Forth
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** model on its head in other respects.
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** Ficl provides facilities for interoperating
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** with programs written in C: C functions can be exported to Ficl,
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** and Ficl commands can be executed via a C calling interface. The
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** interpreter is re-entrant, so it can be used in multiple instances
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** in a multitasking system. Unlike Forth, Ficl's outer interpreter
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** expects a text block as input, and returns to the caller after each
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** text block, so the data pump is somewhere in external code. This
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** is more like TCL than Forth.
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**
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** Code is written in ANSI C for portability.
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*/
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#ifdef TESTMAIN
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#include <stdlib.h>
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#else
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#include <stand.h>
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#endif
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#include <string.h>
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#include "ficl.h"
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/*
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** Local prototypes
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*/
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/*
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** System statics
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** The system builds a global dictionary during its start
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** sequence. This is shared by all interpreter instances.
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** Therefore only one instance can update the dictionary
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** at a time. The system imports a locking function that
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** you can override in order to control update access to
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** the dictionary. The function is stubbed out by default,
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** but you can insert one: #define FICL_MULTITHREAD 1
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** and supply your own version of ficlLockDictionary.
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*/
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static FICL_DICT *dp = NULL;
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static FICL_DICT *envp = NULL;
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#if FICL_WANT_LOCALS
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static FICL_DICT *localp = NULL;
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#endif
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static FICL_VM *vmList = NULL;
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static int defaultStack = FICL_DEFAULT_STACK;
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static int defaultDict = FICL_DEFAULT_DICT;
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/**************************************************************************
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f i c l I n i t S y s t e m
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** Binds a global dictionary to the interpreter system.
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** You specify the address and size of the allocated area.
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** After that, ficl manages it.
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** First step is to set up the static pointers to the area.
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** Then write the "precompiled" portion of the dictionary in.
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** The dictionary needs to be at least large enough to hold the
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** precompiled part. Try 1K cells minimum. Use "words" to find
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** out how much of the dictionary is used at any time.
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**************************************************************************/
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void ficlInitSystem(int nDictCells)
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{
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if (dp)
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dictDelete(dp);
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if (envp)
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dictDelete(envp);
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#if FICL_WANT_LOCALS
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if (localp)
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dictDelete(localp);
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#endif
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if (nDictCells <= 0)
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nDictCells = defaultDict;
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dp = dictCreateHashed((unsigned)nDictCells, HASHSIZE);
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envp = dictCreate( (unsigned)FICL_DEFAULT_ENV);
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#if FICL_WANT_LOCALS
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/*
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** The locals dictionary is only searched while compiling,
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** but this is where speed is most important. On the other
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** hand, the dictionary gets emptied after each use of locals
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** The need to balance search speed with the cost of the empty
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** operation led me to select a single-threaded list...
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*/
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localp = dictCreate( (unsigned)FICL_MAX_LOCALS * CELLS_PER_WORD);
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#endif
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ficlCompileCore(dp);
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return;
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}
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/**************************************************************************
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f i c l N e w V M
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** Create a new virtual machine and link it into the system list
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** of VMs for later cleanup by ficlTermSystem. If this is the first
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** VM to be created, use it to compile the words in softcore.c
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**************************************************************************/
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FICL_VM *ficlNewVM(void)
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{
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FICL_VM *pVM = vmCreate(NULL, defaultStack, defaultStack);
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pVM->link = vmList;
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/*
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** Borrow the first vm to build the soft words in softcore.c
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*/
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if (vmList == NULL)
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ficlCompileSoftCore(pVM);
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vmList = pVM;
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return pVM;
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}
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/**************************************************************************
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f i c l B u i l d
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** Builds a word into the dictionary.
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** Preconditions: system must be initialized, and there must
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** be enough space for the new word's header! Operation is
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** controlled by ficlLockDictionary, so any initialization
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** required by your version of the function (if you overrode
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** it) must be complete at this point.
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** Parameters:
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** name -- duh, the name of the word
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** code -- code to execute when the word is invoked - must take a single param
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** pointer to a FICL_VM
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** flags -- 0 or more of F_IMMEDIATE, F_COMPILE, use bitwise OR!
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**
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**************************************************************************/
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int ficlBuild(char *name, FICL_CODE code, char flags)
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{
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int err = ficlLockDictionary(TRUE);
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if (err) return err;
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dictAppendWord(dp, name, code, flags);
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ficlLockDictionary(FALSE);
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return 0;
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}
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/**************************************************************************
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f i c l E x e c
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** Evaluates a block of input text in the context of the
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** specified interpreter. Emits any requested output to the
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** interpreter's output function.
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**
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** Contains the "inner interpreter" code in a tight loop
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**
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** Returns one of the VM_XXXX codes defined in ficl.h:
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** VM_OUTOFTEXT is the normal exit condition
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** VM_ERREXIT means that the interp encountered a syntax error
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** and the vm has been reset to recover (some or all
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** of the text block got ignored
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** VM_USEREXIT means that the user executed the "bye" command
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** to shut down the interpreter. This would be a good
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** time to delete the vm, etc -- or you can ignore this
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** signal.
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**************************************************************************/
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int ficlExec(FICL_VM *pVM, char *pText)
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{
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int except;
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FICL_WORD *tempFW;
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jmp_buf vmState;
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jmp_buf *oldState;
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TIB saveTib;
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assert(pVM);
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vmPushTib(pVM, pText, &saveTib);
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/*
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** Save and restore VM's jmp_buf to enable nested calls to ficlExec
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*/
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oldState = pVM->pState;
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pVM->pState = &vmState; /* This has to come before the setjmp! */
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except = setjmp(vmState);
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switch (except)
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{
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case 0:
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if (pVM->fRestart)
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{
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pVM->fRestart = 0;
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pVM->runningWord->code(pVM);
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}
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/*
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** the mysterious inner interpreter...
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** vmThrow gets you out of this loop with a longjmp()
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*/
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for (;;)
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{
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tempFW = *pVM->ip++;
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/*
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** inline code for
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** vmExecute(pVM, tempFW);
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*/
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pVM->runningWord = tempFW;
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tempFW->code(pVM);
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}
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break;
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case VM_RESTART:
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pVM->fRestart = 1;
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except = VM_OUTOFTEXT;
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break;
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case VM_OUTOFTEXT:
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#ifdef TESTMAIN
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if ((pVM->state != COMPILE) && (pVM->sourceID.i == 0))
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ficlTextOut(pVM, FICL_PROMPT, 0);
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#endif
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break;
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case VM_USEREXIT:
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break;
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case VM_QUIT:
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if (pVM->state == COMPILE)
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dictAbortDefinition(dp);
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vmQuit(pVM);
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break;
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case VM_ERREXIT:
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default: /* user defined exit code?? */
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if (pVM->state == COMPILE)
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{
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dictAbortDefinition(dp);
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#if FICL_WANT_LOCALS
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dictEmpty(localp, localp->pForthWords->size);
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#endif
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}
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dictResetSearchOrder(dp);
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vmReset(pVM);
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break;
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}
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pVM->pState = oldState;
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vmPopTib(pVM, &saveTib);
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return (except);
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}
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/**************************************************************************
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f i c l E x e c F D
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** reads in text from file fd and passes it to ficlExec()
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* returns VM_OUTOFTEXT on success or the ficlExec() error code on
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* failure.
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*/
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#define nLINEBUF 256
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int ficlExecFD(FICL_VM *pVM, int fd)
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{
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char cp[nLINEBUF];
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int i, nLine = 0, rval = VM_OUTOFTEXT;
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char ch;
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CELL id;
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id = pVM->sourceID;
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pVM->sourceID.i = fd;
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/* feed each line to ficlExec */
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while (1) {
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int status, i;
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i = 0;
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while ((status = read(fd, &ch, 1)) > 0 && ch != '\n')
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cp[i++] = ch;
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nLine++;
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if (!i) {
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if (status < 1)
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break;
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continue;
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}
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cp[i] = '\0';
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if ((rval = ficlExec(pVM, cp)) >= VM_ERREXIT)
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{
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pVM->sourceID = id;
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vmThrowErr(pVM, "ficlExecFD: Error at line %d", nLine);
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break;
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}
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}
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/*
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** Pass an empty line with SOURCE-ID == 0 to flush
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** any pending REFILLs (as required by FILE wordset)
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*/
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pVM->sourceID.i = -1;
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ficlExec(pVM, "");
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pVM->sourceID = id;
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return rval;
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}
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/**************************************************************************
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f i c l L o o k u p
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** Look in the system dictionary for a match to the given name. If
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** found, return the address of the corresponding FICL_WORD. Otherwise
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** return NULL.
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**************************************************************************/
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FICL_WORD *ficlLookup(char *name)
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{
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STRINGINFO si;
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SI_PSZ(si, name);
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return dictLookup(dp, si);
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}
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/**************************************************************************
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f i c l G e t D i c t
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** Returns the address of the system dictionary
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**************************************************************************/
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FICL_DICT *ficlGetDict(void)
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{
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return dp;
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}
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/**************************************************************************
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f i c l G e t E n v
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** Returns the address of the system environment space
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**************************************************************************/
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FICL_DICT *ficlGetEnv(void)
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{
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return envp;
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}
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/**************************************************************************
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f i c l S e t E n v
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** Create an environment variable with a one-CELL payload. ficlSetEnvD
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** makes one with a two-CELL payload.
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**************************************************************************/
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void ficlSetEnv(char *name, UNS32 value)
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{
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STRINGINFO si;
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FICL_WORD *pFW;
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SI_PSZ(si, name);
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pFW = dictLookup(envp, si);
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if (pFW == NULL)
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{
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dictAppendWord(envp, name, constantParen, FW_DEFAULT);
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dictAppendCell(envp, LVALUEtoCELL(value));
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}
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else
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{
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pFW->param[0] = LVALUEtoCELL(value);
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}
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return;
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}
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void ficlSetEnvD(char *name, UNS32 hi, UNS32 lo)
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{
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FICL_WORD *pFW;
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STRINGINFO si;
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SI_PSZ(si, name);
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pFW = dictLookup(envp, si);
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if (pFW == NULL)
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{
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dictAppendWord(envp, name, twoConstParen, FW_DEFAULT);
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dictAppendCell(envp, LVALUEtoCELL(lo));
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dictAppendCell(envp, LVALUEtoCELL(hi));
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}
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else
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{
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pFW->param[0] = LVALUEtoCELL(lo);
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pFW->param[1] = LVALUEtoCELL(hi);
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}
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return;
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}
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/**************************************************************************
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f i c l G e t L o c
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** Returns the address of the system locals dictionary. This dict is
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** only used during compilation, and is shared by all VMs.
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**************************************************************************/
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#if FICL_WANT_LOCALS
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FICL_DICT *ficlGetLoc(void)
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{
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return localp;
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}
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#endif
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/**************************************************************************
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f i c l T e r m S y s t e m
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** Tear the system down by deleting the dictionaries and all VMs.
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** This saves you from having to keep track of all that stuff.
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**************************************************************************/
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void ficlTermSystem(void)
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{
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if (dp)
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dictDelete(dp);
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dp = NULL;
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if (envp)
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dictDelete(envp);
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envp = NULL;
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#if FICL_WANT_LOCALS
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if (localp)
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dictDelete(localp);
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localp = NULL;
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#endif
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while (vmList != NULL)
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{
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FICL_VM *pVM = vmList;
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vmList = vmList->link;
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vmDelete(pVM);
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}
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return;
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}
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