/* * ---------- Mini-Scheme Interpreter Version 0.85 ---------- * * coded by Atsushi Moriwaki (11/5/1989) * * E-MAIL : moriwaki@kurims.kurims.kyoto-u.ac.jp * * THIS SOFTWARE IS IN THE PUBLIC DOMAIN * ------------------------------------ * This software is completely free to copy, modify and/or re-distribute. * But I would appreciate it if you left my name on the code as the author. * */ /*-- * * This version has been modified by R.C. Secrist. * * Mini-Scheme is now maintained by Akira KIDA. * * This is a revised and modified version by Akira KIDA. * current version is 0.85k4 (15 May 1994) * * Please send suggestions, bug reports and/or requests to: * *-- */ /* TODO: Add basic port operations. * * UNSLISP only needs one input port and one output port (besides stdin * and stdout). The easiest thing to do is to make ports integers that * reference a global list of FILE*. */ /* * Here is System declaration. * Please define exactly one symbol in the following section. */ /* #define LSC */ /* LightSpeed C for Macintosh */ /* #define LSC4 */ /* THINK C version 4.0 for Macintosh */ /* #define MPW2 */ /* Macintosh Programmer's Workshop v2.0x */ /* #define BSD */ /* 4.x BSD */ /* #define MSC */ /* Microsoft C Compiler v.4.00 - 7.00 */ /* #define TURBOC */ /* Turbo C compiler v.2.0, or TC++ 1.0 */ /* #define SYSV */ /* System-V, or POSIX */ /* #define VAXC */ /* VAX/VMS VAXC 2.x or later */ /* (automatic) */ #ifdef __BORLANDC__ /* Borland C++ - MS-DOS */ #define TURBOC #endif #ifdef __TURBOC__ /* Turbo C V1.5 - MS-DOS */ #define TURBOC #endif #ifdef mips /* DECstation running OSF/1 */ #define BSD #endif #ifdef __osf__ /* Alpha AXP running OSF/1 */ #define BSD #endif #ifdef __DECC /* Alpha AXP running VMS */ #define VAXC #endif #ifdef _AIX /* RS/6000 running AIX */ #define BSD #endif /* * Define or undefine following symbols as you need. */ /* #define VERBOSE */ /* define this if you want verbose GC */ #define VERBOSE #define AVOID_HACK_LOOP /* define this if your compiler is poor * enougth to complain "do { } while (0)" * construction. */ #if 0 #define USE_SETJMP /* undef this if you do not want to use setjmp() */ #define USE_QQUOTE /* undef this if you do not need quasiquote */ #define USE_MACRO /* undef this if you do not need macro */ #endif #ifdef USE_QQUOTE /*-- * If your machine can't support "forward single quotation character" * i.e., '`', you may have trouble to use backquote. * So use '^' in place of '`'. */ # define BACKQUOTE '`' #endif /* * Basic memory allocation units */ #ifdef TURBOC /* rcs */ #define CELL_SEGSIZE 2048 #define CELL_NSEGMENT 100 #define STR_SEGSIZE 2048 #define STR_NSEGMENT 100 #else #define CELL_SEGSIZE 5000 /* # of cells in one segment */ #define CELL_NSEGMENT 100 /* # of segments for cells */ #define STR_SEGSIZE 2500 /* bytes of one string segment */ #define STR_NSEGMENT 100 /* # of segments for strings */ #endif #define banner "Hello, This is Mini-Scheme Interpreter Version 0.85k4-a for UNSLISP.\n" #include #include #ifdef USE_SETJMP #include #endif /* System dependency */ #ifdef LSC #include #include #define malloc(x) NewPtr((long)(x)) #define prompt "> " #define FIRST_CELLSEGS 5 #endif #ifdef LSC4 #include #include #define malloc(x) NewPtr((long)(x)) #define prompt "> " #define FIRST_CELLSEGS 5 #endif #ifdef MPW2 #include #include #define malloc(x) NewPtr((long)(x)) #define prompt "> [enter at next line]\n" #define FIRST_CELLSEGS 5 #endif #ifdef BSD #include #include #define prompt "> " #define FIRST_CELLSEGS 10 #endif #ifdef MSC #include #include #include #include #define prompt "> " #define FIRST_CELLSEGS 3 #endif #ifdef TURBOC #include #include #define prompt "> " #define FIRST_CELLSEGS 3 #endif #ifdef SYSV #include #include #if __STDC__ # include #endif #define prompt "> " #define FIRST_CELLSEGS 10 #endif #ifdef VAXC #include #include #define prompt "> " #define FIRST_CELLSEGS 10 #endif #ifdef __GNUC__ /* * If we use gcc, AVOID_HACK_LOOP is unnecessary */ #undef AVOID_HACK_LOOP #endif #ifndef FIRST_CELLSEGS #error Please define your system type. /* * We refrain this to raise an error anyway even if on pre-ANSI system. */ error Please define your system type. #endif /* cell structure */ struct cell { unsigned short _flag; union { struct { char *_svalue; short _keynum; } _string; struct { long _ivalue; } _number; struct { struct cell *_car; struct cell *_cdr; } _cons; } _object; }; typedef struct cell *pointer; #define T_STRING 1 /* 0000000000000001 */ #define T_NUMBER 2 /* 0000000000000010 */ #define T_SYMBOL 4 /* 0000000000000100 */ #define T_SYNTAX 8 /* 0000000000001000 */ #define T_PROC 16 /* 0000000000010000 */ #define T_PAIR 32 /* 0000000000100000 */ #define T_CLOSURE 64 /* 0000000001000000 */ #define T_CONTINUATION 128 /* 0000000010000000 */ #ifdef USE_MACRO # define T_MACRO 256 /* 0000000100000000 */ #endif #define T_PROMISE 512 /* 0000001000000000 */ #define T_CHAR 1024 /* 0000010000000000 */ #define T_ATOM 16384 /* 0100000000000000 */ /* only for gc */ #define CLRATOM 49151 /* 1011111111111111 */ /* only for gc */ #define MARK 32768 /* 1000000000000000 */ #define UNMARK 32767 /* 0111111111111111 */ /* macros for cell operations */ #define type(p) ((p)->_flag) #define isstring(p) (type(p)&T_STRING) #define strvalue(p) ((p)->_object._string._svalue) #define keynum(p) ((p)->_object._string._keynum) #define isnumber(p) (type(p)&T_NUMBER) #define ivalue(p) ((p)->_object._number._ivalue) #define ischar(p) (type(p)&T_CHAR) #define ispair(p) (type(p)&T_PAIR) #define car(p) ((p)->_object._cons._car) #define cdr(p) ((p)->_object._cons._cdr) #define issymbol(p) (type(p)&T_SYMBOL) #define symname(p) strvalue(car(p)) #define hasprop(p) (type(p)&T_SYMBOL) #define symprop(p) cdr(p) #define issyntax(p) (type(p)&T_SYNTAX) #define isproc(p) (type(p)&T_PROC) #define syntaxname(p) strvalue(car(p)) #define syntaxnum(p) keynum(car(p)) #define procnum(p) ivalue(p) #define isclosure(p) (type(p)&T_CLOSURE) #ifdef USE_MACRO # define ismacro(p) (type(p)&T_MACRO) #endif #define closure_code(p) car(p) #define closure_env(p) cdr(p) #define iscontinuation(p) (type(p)&T_CONTINUATION) #define cont_dump(p) cdr(p) #define ispromise(p) (type(p)&T_PROMISE) #define setpromise(p) type(p) |= T_PROMISE #define isatom(p) (type(p)&T_ATOM) #define setatom(p) type(p) |= T_ATOM #define clratom(p) type(p) &= CLRATOM #define ismark(p) (type(p)&MARK) #define setmark(p) type(p) |= MARK #define clrmark(p) type(p) &= UNMARK #define caar(p) car(car(p)) #define cadr(p) car(cdr(p)) #define cdar(p) cdr(car(p)) #define cddr(p) cdr(cdr(p)) #define cadar(p) car(cdr(car(p))) #define caddr(p) car(cdr(cdr(p))) #define cadaar(p) car(cdr(car(car(p)))) #define cadddr(p) car(cdr(cdr(cdr(p)))) #define cddddr(p) cdr(cdr(cdr(cdr(p)))) /* arrays for segments */ pointer cell_seg[CELL_NSEGMENT]; int last_cell_seg = -1; char *str_seg[STR_NSEGMENT]; int str_seglast = -1; /* We use 4 registers. */ pointer args; /* register for arguments of function */ pointer envir; /* stack register for current environment */ pointer code; /* register for current code */ pointer dump; /* stack register for next evaluation */ struct cell _NIL; pointer NIL = &_NIL; /* special cell representing empty cell */ struct cell _T; pointer T = &_T; /* special cell representing #t */ struct cell _F; pointer F = &_F; /* special cell representing #f */ pointer oblist = &_NIL; /* pointer to symbol table */ pointer global_env; /* pointer to global environment */ /* global pointers to special symbols */ pointer LAMBDA; /* pointer to syntax lambda */ pointer QUOTE; /* pointer to syntax quote */ #ifdef USE_QQUOTE pointer QQUOTE; /* pointer to symbol quasiquote */ pointer UNQUOTE; /* pointer to symbol unquote */ pointer UNQUOTESP; /* pointer to symbol unquote-splicing */ #endif pointer free_cell = &_NIL; /* pointer to top of free cells */ long fcells = 0; /* # of free cells */ FILE *infp; /* input file */ FILE *outfp; /* output file */ #ifdef USE_SETJMP jmp_buf error_jmp; #endif char gc_verbose; /* if gc_verbose is not zero, print gc status */ stricmp(x, y) char *x; char *y; { for (; tolower((unsigned char)(*x++)) == tolower((unsigned char)(*y++)); x++, y++) if (!*x) break; return *x - *y; } /* allocate new cell segment */ alloc_cellseg(n) int n; { register pointer p; register long i; register int k; for (k = 0; k < n; k++) { if (last_cell_seg >= CELL_NSEGMENT - 1) return k; p = (pointer) malloc(CELL_SEGSIZE * sizeof(struct cell)); if (p == (pointer) 0) return k; cell_seg[++last_cell_seg] = p; fcells += CELL_SEGSIZE; for (i = 0; i < CELL_SEGSIZE - 1; i++, p++) { type(p) = 0; car(p) = NIL; cdr(p) = p + 1; } type(p) = 0; car(p) = NIL; cdr(p) = free_cell; free_cell = cell_seg[last_cell_seg]; } return n; } /* allocate new string segment */ alloc_strseg(n) int n; { register char *p; register long i; register int k; for (k = 0; k < n; k++) { if (str_seglast >= STR_NSEGMENT) return k; p = (char *) malloc(STR_SEGSIZE * sizeof(char)); if (p == (char *) 0) return k; str_seg[++str_seglast] = p; for (i = 0; i < STR_SEGSIZE; i++) *p++ = (char) (-1); } return n; } /* initialization of Mini-Scheme */ init_scheme() { register pointer i; if (alloc_cellseg(FIRST_CELLSEGS) != FIRST_CELLSEGS) FatalError("Unable to allocate initial cell segments"); if (!alloc_strseg(1)) FatalError("Unable to allocate initial string segments"); #ifdef VERBOSE gc_verbose = 1; #else gc_verbose = 0; #endif init_globals(); } /* get new cell. parameter a, b is marked by gc. */ pointer get_cell(a, b) register pointer a, b; { register pointer x; if (free_cell == NIL) { gc(a, b); if (free_cell == NIL) #ifdef USE_SETJMP if (!alloc_cellseg(1)) { args = envir = code = dump = NIL; gc(NIL, NIL); if (free_cell != NIL) Error("run out of cells --- rerurn to top level"); else FatalError("run out of cells --- unable to recover cells"); } #else if (!alloc_cellseg(1)) FatalError("run out of cells --- unable to recover cells"); #endif } x = free_cell; free_cell = cdr(x); --fcells; return (x); } /* get new cons cell */ pointer cons(a, b) register pointer a, b; { register pointer x = get_cell(a, b); type(x) = T_PAIR; car(x) = a; cdr(x) = b; return (x); } /* get number atom */ pointer mk_number(num) register long num; { register pointer x = get_cell(NIL, NIL); type(x) = (T_NUMBER | T_ATOM); ivalue(x) = num; return (x); } /* allocate name to string area */ char *store_string(name) char *name; { register char *q; register short i; long len, remain; /* first check name has already listed */ for (i = 0; i <= str_seglast; i++) for (q = str_seg[i]; *q != (char) (-1); ) { if (!strcmp(q, name)) goto FOUND; while (*q++) ; /* get next string */ } len = strlen(name) + 2; remain = (long) STR_SEGSIZE - ((long) q - (long) str_seg[str_seglast]); if (remain < len) { if (!alloc_strseg(1)) FatalError("run out of string area"); q = str_seg[str_seglast]; } strcpy(q, name); FOUND: return (q); } /* get new string */ pointer mk_string(str) char *str; { register pointer x = get_cell(NIL, NIL); strvalue(x) = store_string(str); type(x) = (T_STRING | T_ATOM); keynum(x) = (short) (-1); return (x); } /* get new symbol */ pointer mk_symbol(name) char *name; { register pointer x; /* fisrt check oblist */ for (x = oblist; x != NIL; x = cdr(x)) if (!strcmp(name, symname(car(x)))) break; if (x != NIL) return (car(x)); else { x = cons(mk_string(name), NIL); type(x) = T_SYMBOL; oblist = cons(x, oblist); return (x); } } /* make symbol or number atom from string */ pointer mk_atom(q) char *q; { char c, *p; p = q; if (!isdigit(c = *p++)) { if ((c != '+' && c != '-') || !isdigit(*p)) return (mk_symbol(q)); } for ( ; (c = *p) != 0; ++p) if (!isdigit(c)) return (mk_symbol(q)); return (mk_number(atol(q))); } /* make char */ pointer mk_char(name) char *name; { register pointer x = get_cell(NIL, NIL); type(x) = (T_CHAR | T_ATOM); if (stricmp(name, "space") == 0) { ivalue(x) = ' '; } else if (stricmp(name, "newline") == 0) { ivalue(x) = '\n'; } else { ivalue(x) = *name; } return x; } /* make constant */ pointer mk_const(name) char *name; { long x; char tmp[256]; if (!strcmp(name, "t")) return (T); else if (!strcmp(name, "f")) return (F); else if (*name == 'o') {/* #o (octal) */ sprintf(tmp, "0%s", &name[1]); sscanf(tmp, "%lo", &x); return (mk_number(x)); } else if (*name == 'd') { /* #d (decimal) */ sscanf(&name[1], "%ld", &x); return (mk_number(x)); } else if (*name == 'x') { /* #x (hex) */ sprintf(tmp, "0x%s", &name[1]); sscanf(tmp, "%lx", &x); return (mk_number(x)); } else if (*name == '\\') { /* Character constant */ return (mk_char(&name[1])); } else { return (NIL); } } /* ========== garbage collector ========== */ /*-- * We use algorithm E (Kunuth, The Art of Computer Programming Vol.1, * sec.3.5) for marking. */ mark(a) pointer a; { register pointer t, q, p; E1: t = (pointer) 0; p = a; E2: setmark(p); E3: if (isatom(p)) goto E6; E4: q = car(p); if (q && !ismark(q)) { setatom(p); car(p) = t; t = p; p = q; goto E2; } E5: q = cdr(p); if (q && !ismark(q)) { cdr(p) = t; t = p; p = q; goto E2; } E6: if (!t) return; q = t; if (isatom(q)) { clratom(q); t = car(q); car(q) = p; p = q; goto E5; } else { t = cdr(q); cdr(q) = p; p = q; goto E6; } } /* garbage collection. parameter a, b is marked. */ gc(a, b) register pointer a, b; { register pointer p; register short i; register long j; if (gc_verbose) printf("gc..."); /* mark system globals */ mark(oblist); mark(global_env); /* mark current registers */ mark(args); mark(envir); mark(code); mark(dump); /* mark variables a, b */ mark(a); mark(b); /* garbage collect */ clrmark(NIL); fcells = 0; free_cell = NIL; for (i = 0; i <= last_cell_seg; i++) { for (j = 0, p = cell_seg[i]; j < CELL_SEGSIZE; j++, p++) { if (ismark(p)) clrmark(p); else { type(p) = 0; cdr(p) = free_cell; car(p) = NIL; free_cell = p; ++fcells; } } } if (gc_verbose) printf(" done %ld cells are recovered.\n", fcells); } /* ========== Rootines for Reading ========== */ #define TOK_LPAREN 0 #define TOK_RPAREN 1 #define TOK_DOT 2 #define TOK_ATOM 3 #define TOK_QUOTE 4 #define TOK_COMMENT 5 #define TOK_DQUOTE 6 #ifdef USE_QQUOTE # define TOK_BQUOTE 7 # define TOK_COMMA 8 # define TOK_ATMARK 9 #endif #define TOK_SHARP 10 #define LINESIZE 1024 char linebuff[LINESIZE]; char strbuff[256]; char *currentline = linebuff; char *endline = linebuff; /* get new character from input file */ int inchar() { if (currentline >= endline) { /* input buffer is empty */ if (feof(infp)) { fclose(infp); infp = stdin; printf(prompt); } strcpy(linebuff, "\n"); if (fgets(currentline = linebuff, LINESIZE, infp) == NULL) if (infp == stdin) { fprintf(stderr, "Good-bye\n"); exit(0); } endline = linebuff + strlen(linebuff); } return (*currentline++); } /* clear input buffer */ clearinput() { currentline = endline = linebuff; } /* back to standard input */ flushinput() { if (infp != stdin) { fclose(infp); infp = stdin; } clearinput(); } /* back character to input buffer */ backchar() { currentline--; } /* read chacters to delimiter */ char *readstr(delim) char *delim; { char *p = strbuff; while (isdelim(delim, (*p++ = inchar()))) ; backchar(); *--p = '\0'; return (strbuff); } /* read string expression "xxx...xxx" */ char *readstrexp() { char c, *p = strbuff; for (;;) { if ((c = inchar()) != '"') *p++ = c; else if (p > strbuff && *(p - 1) == '\\') *(p - 1) = '"'; else { *p = '\0'; return (strbuff); } } } /* check c is delimiter */ isdelim(s, c) char *s; char c; { while (*s) if (*s++ == c) return (0); return (1); } /* skip white characters */ skipspace() { while (isspace(inchar())) ; backchar(); } /* get token */ token() { skipspace(); switch (inchar()) { case '(': return (TOK_LPAREN); case ')': return (TOK_RPAREN); case '.': return (TOK_DOT); case '\'': return (TOK_QUOTE); case ';': return (TOK_COMMENT); case '"': return (TOK_DQUOTE); #ifdef USE_QQUOTE case BACKQUOTE: return (TOK_BQUOTE); case ',': if (inchar() == '@') return (TOK_ATMARK); else { backchar(); return (TOK_COMMA); } #endif case '#': return (TOK_SHARP); default: backchar(); return (TOK_ATOM); } } /* ========== Rootines for Printing ========== */ #define ok_abbrev(x) (ispair(x) && cdr(x) == NIL) strunquote(p, s) char *p; char *s; { *p++ = '"'; for ( ; *s; ++s) { if (*s == '"') { *p++ = '\\'; *p++ = '"'; } else if (*s == '\n') { *p++ = '\\'; *p++ = 'n'; } else *p++ = *s; } *p++ = '"'; *p = '\0'; } /* print atoms */ int printatom(l, f) pointer l; int f; { char *p; if (l == NIL) p = "()"; else if (l == T) p = "#t"; else if (l == F) p = "#f"; else if (isnumber(l)) { p = strbuff; sprintf(p, "%ld", ivalue(l)); } else if (isstring(l)) { if (!f) p = strvalue(l); else { p = strbuff; strunquote(p, strvalue(l)); } } else if (issymbol(l)) p = symname(l); else if (isproc(l)) { p = strbuff; sprintf(p, "#", procnum(l)); #ifdef USE_MACRO } else if (ismacro(l)) { p = "#"; #endif } else if (isclosure(l)) p = "#"; else if (iscontinuation(l)) p = "#"; else if (ischar(l)) { if (ivalue(l) == '\n') p = "#\\newline"; else if (ivalue(l) == ' ') p = "#\\space"; else { p = strbuff; sprintf(p, "#\\%c", ivalue(l)); } } if (f < 0) return strlen(p); fputs(p, outfp); return 0; } /* ========== Rootines for Evaluation Cycle ========== */ /* make closure. c is code. e is environment */ pointer mk_closure(c, e) register pointer c, e; { register pointer x = get_cell(c, e); type(x) = T_CLOSURE; car(x) = c; cdr(x) = e; return (x); } /* make continuation. */ pointer mk_continuation(d) register pointer d; { register pointer x = get_cell(NIL, d); type(x) = T_CONTINUATION; cont_dump(x) = d; return (x); } /* reverse list -- make new cells */ pointer reverse(a) register pointer a; /* a must be checked by gc */ { register pointer p = NIL; for ( ; ispair(a); a = cdr(a)) p = cons(car(a), p); return (p); } /* reverse list --- no make new cells */ pointer non_alloc_rev(term, list) pointer term, list; { register pointer p = list, result = term, q; while (p != NIL) { q = cdr(p); cdr(p) = result; result = p; p = q; } return (result); } /* append list -- make new cells */ pointer append(a, b) register pointer a, b; { register pointer p = b, q; if (a != NIL) { a = reverse(a); while (a != NIL) { q = cdr(a); cdr(a) = p; p = a; a = q; } } return (p); } /* equivalence of atoms */ eqv(a, b) register pointer a, b; { if (isstring(a)) { if (isstring(b)) return (strvalue(a) == strvalue(b)); else return (0); } else if (isnumber(a)) { if (isnumber(b)) return (ivalue(a) == ivalue(b)); else return (0); } else if (ischar(a)) { if (ischar(b)) return (ivalue(a) == ivalue(b)); else return (0); } else return (a == b); } /* true or false value macro */ #define istrue(p) ((p) != NIL && (p) != F) #define isfalse(p) ((p) == NIL || (p) == F) /* Error macro */ #ifdef AVOID_HACK_LOOP # define BEGIN { # define END } #else /* * I believe this is better, but some compiler complains.... */ # define BEGIN do { # define END } while (0) #endif #define Error_0(s) BEGIN \ args = cons(mk_string((s)), NIL); \ operator = (short)OP_ERR0; \ return T; END #define Error_1(s, a) BEGIN \ args = cons((a), NIL); \ args = cons(mk_string((s)), args); \ operator = (short)OP_ERR0; \ return T; END /* control macros for Eval_Cycle */ #define s_goto(a) BEGIN \ operator = (short)(a); \ return T; END #define s_save(a, b, c) ( \ dump = cons(envir, cons((c), dump)), \ dump = cons((b), dump), \ dump = cons(mk_number((long)(a)), dump)) \ #define s_return(a) BEGIN \ value = (a); \ operator = ivalue(car(dump)); \ args = cadr(dump); \ envir = caddr(dump); \ code = cadddr(dump); \ dump = cddddr(dump); \ return T; END #define s_retbool(tf) s_return((tf) ? T : F) /* ========== Evaluation Cycle ========== */ /* operator code */ #define OP_LOAD 0 #define OP_T0LVL 1 #define OP_T1LVL 2 #define OP_READ 3 #define OP_VALUEPRINT 4 #define OP_EVAL 5 #define OP_E0ARGS 6 #define OP_E1ARGS 7 #define OP_APPLY 8 #define OP_DOMACRO 9 #define OP_LAMBDA 10 #define OP_QUOTE 11 #define OP_DEF0 12 #define OP_DEF1 13 #define OP_BEGIN 14 #define OP_IF0 15 #define OP_IF1 16 #define OP_SET0 17 #define OP_SET1 18 #define OP_LET0 19 #define OP_LET1 20 #define OP_LET2 21 #define OP_LET0AST 22 #define OP_LET1AST 23 #define OP_LET2AST 24 #define OP_LET0REC 25 #define OP_LET1REC 26 #define OP_LET2REC 27 #define OP_COND0 28 #define OP_COND1 29 #define OP_DELAY 30 #define OP_AND0 31 #define OP_AND1 32 #define OP_OR0 33 #define OP_OR1 34 #define OP_C0STREAM 35 #define OP_C1STREAM 36 #define OP_0MACRO 37 #define OP_1MACRO 38 #define OP_CASE0 39 #define OP_CASE1 40 #define OP_CASE2 41 #define OP_PEVAL 42 #define OP_PAPPLY 43 #define OP_CONTINUATION 44 #define OP_ADD 45 #define OP_SUB 46 #define OP_MUL 47 #define OP_DIV 48 #define OP_REM 49 #define OP_CAR 50 #define OP_CDR 51 #define OP_CONS 52 #define OP_SETCAR 53 #define OP_SETCDR 54 #define OP_NOT 55 #define OP_BOOL 56 #define OP_NULL 57 #define OP_ZEROP 58 #define OP_POSP 59 #define OP_NEGP 60 #define OP_NEQ 61 #define OP_LESS 62 #define OP_GRE 63 #define OP_LEQ 64 #define OP_GEQ 65 #define OP_SYMBOL 66 #define OP_NUMBER 67 #define OP_STRING 68 #define OP_PROC 69 #define OP_PAIR 70 #define OP_EQ 71 #define OP_EQV 72 #define OP_FORCE 73 #define OP_WRITE 74 #define OP_DISPLAY 75 #define OP_NEWLINE 76 #define OP_ERR0 77 #define OP_ERR1 78 #define OP_REVERSE 79 #define OP_APPEND 80 #define OP_PUT 81 #define OP_GET 82 #define OP_QUIT 83 #define OP_GC 84 #define OP_GCVERB 85 #define OP_NEWSEGMENT 86 #define OP_RDSEXPR 87 #define OP_RDLIST 88 #define OP_RDDOT 89 #define OP_RDQUOTE 90 #define OP_RDQQUOTE 91 #define OP_RDUNQUOTE 92 #define OP_RDUQTSP 93 #define OP_P0LIST 94 #define OP_P1LIST 95 #define OP_LIST_LENGTH 96 #define OP_ASSQ 97 #define OP_PRINT_WIDTH 98 #define OP_P0_WIDTH 99 #define OP_P1_WIDTH 100 #define OP_GET_CLOSURE 101 #define OP_CLOSUREP 102 #define OP_MACROP 103 #define OP_CHAR 104 static FILE *tmpfp; static int tok; static int print_flag; static pointer value; static short operator; pointer opexe_0(op) register short op; { register pointer x, y; switch (op) { case OP_LOAD: /* load */ if (!isstring(car(args))) { Error_0("load -- argument is not string"); } if ((infp = fopen(strvalue(car(args)), "r")) == NULL) { infp = stdin; Error_1("Unable to open", car(args)); } fprintf(outfp, "loading %s", strvalue(car(args))); s_goto(OP_T0LVL); case OP_T0LVL: /* top level */ fprintf(outfp, "\n"); dump = NIL; envir = global_env; s_save(OP_VALUEPRINT, NIL, NIL); s_save(OP_T1LVL, NIL, NIL); if (infp == stdin) printf(prompt); s_goto(OP_READ); case OP_T1LVL: /* top level */ code = value; s_goto(OP_EVAL); case OP_READ: /* read */ tok = token(); s_goto(OP_RDSEXPR); case OP_VALUEPRINT: /* print evalution result */ print_flag = 1; args = value; s_save(OP_T0LVL, NIL, NIL); s_goto(OP_P0LIST); case OP_EVAL: /* main part of evalution */ if (issymbol(code)) { /* symbol */ for (x = envir; x != NIL; x = cdr(x)) { for (y = car(x); y != NIL; y = cdr(y)) if (caar(y) == code) break; if (y != NIL) break; } if (x != NIL) { s_return(cdar(y)); } else { Error_1("Unbounded variable", code); } } else if (ispair(code)) { if (issyntax(x = car(code))) { /* SYNTAX */ code = cdr(code); s_goto(syntaxnum(x)); } else {/* first, eval top element and eval arguments */ #ifdef USE_MACRO s_save(OP_E0ARGS, NIL, code); #else s_save(OP_E1ARGS, NIL, cdr(code)); #endif code = car(code); s_goto(OP_EVAL); } } else { s_return(code); } #ifdef USE_MACRO case OP_E0ARGS: /* eval arguments */ if (ismacro(value)) { /* macro expansion */ s_save(OP_DOMACRO, NIL, NIL); args = cons(code, NIL); code = value; s_goto(OP_APPLY); } else { code = cdr(code); s_goto(OP_E1ARGS); } #endif case OP_E1ARGS: /* eval arguments */ args = cons(value, args); if (ispair(code)) { /* continue */ s_save(OP_E1ARGS, args, cdr(code)); code = car(code); args = NIL; s_goto(OP_EVAL); } else { /* end */ args = reverse(args); code = car(args); args = cdr(args); s_goto(OP_APPLY); } case OP_APPLY: /* apply 'code' to 'args' */ if (isproc(code)) { s_goto(procnum(code)); /* PROCEDURE */ } else if (isclosure(code)) { /* CLOSURE */ /* make environment */ envir = cons(NIL, closure_env(code)); for (x = car(closure_code(code)), y = args; ispair(x); x = cdr(x), y = cdr(y)) { if (y == NIL) { Error_0("Few arguments"); } else { car(envir) = cons(cons(car(x), car(y)), car(envir)); } } if (x == NIL) { /*-- * if (y != NIL) { * Error_0("Many arguments"); * } */ } else if (issymbol(x)) car(envir) = cons(cons(x, y), car(envir)); else { Error_0("Syntax error in closure"); } code = cdr(closure_code(code)); args = NIL; s_goto(OP_BEGIN); } else if (iscontinuation(code)) { /* CONTINUATION */ dump = cont_dump(code); s_return(args != NIL ? car(args) : NIL); } else { Error_0("Illegal function"); } #ifdef USE_MACRO case OP_DOMACRO: /* do macro */ code = value; s_goto(OP_EVAL); #endif case OP_LAMBDA: /* lambda */ s_return(mk_closure(code, envir)); case OP_QUOTE: /* quote */ s_return(car(code)); case OP_DEF0: /* define */ if (ispair(car(code))) { x = caar(code); code = cons(LAMBDA, cons(cdar(code), cdr(code))); } else { x = car(code); code = cadr(code); } if (!issymbol(x)) { Error_0("Variable is not symbol"); } s_save(OP_DEF1, NIL, x); s_goto(OP_EVAL); case OP_DEF1: /* define */ for (x = car(envir); x != NIL; x = cdr(x)) if (caar(x) == code) break; if (x != NIL) cdar(x) = value; else car(envir) = cons(cons(code, value), car(envir)); s_return(code); case OP_SET0: /* set! */ s_save(OP_SET1, NIL, car(code)); code = cadr(code); s_goto(OP_EVAL); case OP_SET1: /* set! */ for (x = envir; x != NIL; x = cdr(x)) { for (y = car(x); y != NIL; y = cdr(y)) if (caar(y) == code) break; if (y != NIL) break; } if (x != NIL) { cdar(y) = value; s_return(value); } else { Error_1("Unbounded variable", code); } case OP_BEGIN: /* begin */ if (!ispair(code)) { s_return(code); } if (cdr(code) != NIL) { s_save(OP_BEGIN, NIL, cdr(code)); } code = car(code); s_goto(OP_EVAL); case OP_IF0: /* if */ s_save(OP_IF1, NIL, cdr(code)); code = car(code); s_goto(OP_EVAL); case OP_IF1: /* if */ if (istrue(value)) code = car(code); else code = cadr(code); /* (if #f 1) ==> () because * car(NIL) = NIL */ s_goto(OP_EVAL); case OP_LET0: /* let */ args = NIL; value = code; code = issymbol(car(code)) ? cadr(code) : car(code); s_goto(OP_LET1); case OP_LET1: /* let (caluculate parameters) */ args = cons(value, args); if (ispair(code)) { /* continue */ s_save(OP_LET1, args, cdr(code)); code = cadar(code); args = NIL; s_goto(OP_EVAL); } else { /* end */ args = reverse(args); code = car(args); args = cdr(args); s_goto(OP_LET2); } case OP_LET2: /* let */ envir = cons(NIL, envir); for (x = issymbol(car(code)) ? cadr(code) : car(code), y = args; y != NIL; x = cdr(x), y = cdr(y)) car(envir) = cons(cons(caar(x), car(y)), car(envir)); if (issymbol(car(code))) { /* named let */ for (x = cadr(code), args = NIL; x != NIL; x = cdr(x)) args = cons(caar(x), args); x = mk_closure(cons(reverse(args), cddr(code)), envir); car(envir) = cons(cons(car(code), x), car(envir)); code = cddr(code); args = NIL; } else { code = cdr(code); args = NIL; } s_goto(OP_BEGIN); case OP_LET0AST: /* let* */ if (car(code) == NIL) { envir = cons(NIL, envir); code = cdr(code); s_goto(OP_BEGIN); } s_save(OP_LET1AST, cdr(code), car(code)); code = cadaar(code); s_goto(OP_EVAL); case OP_LET1AST: /* let* (make new frame) */ envir = cons(NIL, envir); s_goto(OP_LET2AST); case OP_LET2AST: /* let* (caluculate parameters) */ car(envir) = cons(cons(caar(code), value), car(envir)); code = cdr(code); if (ispair(code)) { /* continue */ s_save(OP_LET2AST, args, code); code = cadar(code); args = NIL; s_goto(OP_EVAL); } else { /* end */ code = args; args = NIL; s_goto(OP_BEGIN); } default: sprintf(strbuff, "%d is illegal operator", operator); Error_0(strbuff); } return T; } pointer opexe_1(op) register short op; { register pointer x, y; switch (op) { case OP_LET0REC: /* letrec */ envir = cons(NIL, envir); args = NIL; value = code; code = car(code); s_goto(OP_LET1REC); case OP_LET1REC: /* letrec (caluculate parameters) */ args = cons(value, args); if (ispair(code)) { /* continue */ s_save(OP_LET1REC, args, cdr(code)); code = cadar(code); args = NIL; s_goto(OP_EVAL); } else { /* end */ args = reverse(args); code = car(args); args = cdr(args); s_goto(OP_LET2REC); } case OP_LET2REC: /* letrec */ for (x = car(code), y = args; y != NIL; x = cdr(x), y = cdr(y)) car(envir) = cons(cons(caar(x), car(y)), car(envir)); code = cdr(code); args = NIL; s_goto(OP_BEGIN); case OP_COND0: /* cond */ if (!ispair(code)) { Error_0("Syntax error in cond"); } s_save(OP_COND1, NIL, code); code = caar(code); s_goto(OP_EVAL); case OP_COND1: /* cond */ if (istrue(value)) { if ((code = cdar(code)) == NIL) { s_return(value); } s_goto(OP_BEGIN); } else { if ((code = cdr(code)) == NIL) { s_return(NIL); } else { s_save(OP_COND1, NIL, code); code = caar(code); s_goto(OP_EVAL); } } case OP_DELAY: /* delay */ x = mk_closure(cons(NIL, code), envir); setpromise(x); s_return(x); case OP_AND0: /* and */ if (code == NIL) { s_return(T); } s_save(OP_AND1, NIL, cdr(code)); code = car(code); s_goto(OP_EVAL); case OP_AND1: /* and */ if (isfalse(value)) { s_return(value); } else if (code == NIL) { s_return(value); } else { s_save(OP_AND1, NIL, cdr(code)); code = car(code); s_goto(OP_EVAL); } case OP_OR0: /* or */ if (code == NIL) { s_return(F); } s_save(OP_OR1, NIL, cdr(code)); code = car(code); s_goto(OP_EVAL); case OP_OR1: /* or */ if (istrue(value)) { s_return(value); } else if (code == NIL) { s_return(value); } else { s_save(OP_OR1, NIL, cdr(code)); code = car(code); s_goto(OP_EVAL); } case OP_C0STREAM: /* cons-stream */ s_save(OP_C1STREAM, NIL, cdr(code)); code = car(code); s_goto(OP_EVAL); case OP_C1STREAM: /* cons-stream */ args = value; /* save value to register args for gc */ x = mk_closure(cons(NIL, code), envir); setpromise(x); s_return(cons(args, x)); #ifdef USE_MACRO case OP_0MACRO: /* macro */ x = car(code); code = cadr(code); if (!issymbol(x)) { Error_0("Variable is not symbol"); } s_save(OP_1MACRO, NIL, x); s_goto(OP_EVAL); case OP_1MACRO: /* macro */ type(value) |= T_MACRO; for (x = car(envir); x != NIL; x = cdr(x)) if (caar(x) == code) break; if (x != NIL) cdar(x) = value; else car(envir) = cons(cons(code, value), car(envir)); s_return(code); #endif case OP_CASE0: /* case */ s_save(OP_CASE1, NIL, cdr(code)); code = car(code); s_goto(OP_EVAL); case OP_CASE1: /* case */ for (x = code; x != NIL; x = cdr(x)) { if (!ispair(y = caar(x))) break; for ( ; y != NIL; y = cdr(y)) if (eqv(car(y), value)) break; if (y != NIL) break; } if (x != NIL) { if (ispair(caar(x))) { code = cdar(x); s_goto(OP_BEGIN); } else {/* else */ s_save(OP_CASE2, NIL, cdar(x)); code = caar(x); s_goto(OP_EVAL); } } else { s_return(NIL); } case OP_CASE2: /* case */ if (istrue(value)) { s_goto(OP_BEGIN); } else { s_return(NIL); } case OP_PAPPLY: /* apply */ code = car(args); args = cadr(args); s_goto(OP_APPLY); case OP_PEVAL: /* eval */ code = car(args); args = NIL; s_goto(OP_EVAL); case OP_CONTINUATION: /* call-with-current-continuation */ code = car(args); args = cons(mk_continuation(dump), NIL); s_goto(OP_APPLY); default: sprintf(strbuff, "%d is illegal operator", operator); Error_0(strbuff); } return T; } pointer opexe_2(op) register short op; { register pointer x, y; register long v; switch (op) { case OP_ADD: /* + */ for (x = args, v = 0; x != NIL; x = cdr(x)) v += ivalue(car(x)); s_return(mk_number(v)); case OP_SUB: /* - */ for (x = cdr(args), v = ivalue(car(args)); x != NIL; x = cdr(x)) v -= ivalue(car(x)); s_return(mk_number(v)); case OP_MUL: /* * */ for (x = args, v = 1; x != NIL; x = cdr(x)) v *= ivalue(car(x)); s_return(mk_number(v)); case OP_DIV: /* / */ for (x = cdr(args), v = ivalue(car(args)); x != NIL; x = cdr(x)) { if (ivalue(car(x)) != 0) v /= ivalue(car(x)); else { Error_0("Divided by zero"); } } s_return(mk_number(v)); case OP_REM: /* remainder */ for (x = cdr(args), v = ivalue(car(args)); x != NIL; x = cdr(x)) { if (ivalue(car(x)) != 0) v %= ivalue(car(x)); else { Error_0("Divided by zero"); } } s_return(mk_number(v)); case OP_CAR: /* car */ if (ispair(car(args))) { s_return(caar(args)); } else { Error_0("Unable to car for non-cons cell"); } case OP_CDR: /* cdr */ if (ispair(car(args))) { s_return(cdar(args)); } else { Error_0("Unable to cdr for non-cons cell"); } case OP_CONS: /* cons */ cdr(args) = cadr(args); s_return(args); case OP_SETCAR: /* set-car! */ if (ispair(car(args))) { caar(args) = cadr(args); s_return(car(args)); } else { Error_0("Unable to set-car! for non-cons cell"); } case OP_SETCDR: /* set-cdr! */ if (ispair(car(args))) { cdar(args) = cadr(args); s_return(car(args)); } else { Error_0("Unable to set-cdr! for non-cons cell"); } default: sprintf(strbuff, "%d is illegal operator", operator); Error_0(strbuff); } return T; } pointer opexe_3(op) register short op; { register pointer x, y; switch (op) { case OP_NOT: /* not */ s_retbool(isfalse(car(args))); case OP_BOOL: /* boolean? */ s_retbool(car(args) == F || car(args) == T); case OP_NULL: /* null? */ s_retbool(car(args) == NIL); case OP_ZEROP: /* zero? */ s_retbool(ivalue(car(args)) == 0); case OP_POSP: /* positive? */ s_retbool(ivalue(car(args)) > 0); case OP_NEGP: /* negative? */ s_retbool(ivalue(car(args)) < 0); case OP_NEQ: /* = */ s_retbool(ivalue(car(args)) == ivalue(cadr(args))); case OP_LESS: /* < */ s_retbool(ivalue(car(args)) < ivalue(cadr(args))); case OP_GRE: /* > */ s_retbool(ivalue(car(args)) > ivalue(cadr(args))); case OP_LEQ: /* <= */ s_retbool(ivalue(car(args)) <= ivalue(cadr(args))); case OP_GEQ: /* >= */ s_retbool(ivalue(car(args)) >= ivalue(cadr(args))); case OP_SYMBOL: /* symbol? */ s_retbool(issymbol(car(args))); case OP_NUMBER: /* number? */ s_retbool(isnumber(car(args))); case OP_CHAR: /* char? */ s_retbool(ischar(car(args))); case OP_STRING: /* string? */ s_retbool(isstring(car(args))); case OP_PROC: /* procedure? */ /*-- * continuation should be procedure by the example * (call-with-current-continuation procedure?) ==> #t * in R^3 report sec. 6.9 */ s_retbool(isproc(car(args)) || isclosure(car(args)) || iscontinuation(car(args))); case OP_PAIR: /* pair? */ s_retbool(ispair(car(args))); case OP_EQ: /* eq? */ s_retbool(car(args) == cadr(args)); case OP_EQV: /* eqv? */ s_retbool(eqv(car(args), cadr(args))); default: sprintf(strbuff, "%d is illegal operator", operator); Error_0(strbuff); } return T; } pointer opexe_4(op) register short op; { register pointer x, y; switch (op) { case OP_FORCE: /* force */ code = car(args); if (ispromise(code)) { args = NIL; s_goto(OP_APPLY); } else { s_return(code); } case OP_WRITE: /* write */ print_flag = 1; args = car(args); s_goto(OP_P0LIST); case OP_DISPLAY: /* display */ print_flag = 0; args = car(args); s_goto(OP_P0LIST); case OP_NEWLINE: /* newline */ fprintf(outfp, "\n"); s_return(T); case OP_ERR0: /* error */ if (!isstring(car(args))) { Error_0("error -- first argument must be string"); } tmpfp = outfp; outfp = stderr; fprintf(outfp, "Error: "); fprintf(outfp, "%s", strvalue(car(args))); args = cdr(args); s_goto(OP_ERR1); case OP_ERR1: /* error */ fprintf(outfp, " "); if (args != NIL) { s_save(OP_ERR1, cdr(args), NIL); args = car(args); print_flag = 1; s_goto(OP_P0LIST); } else { fprintf(outfp, "\n"); flushinput(); outfp = tmpfp; s_goto(OP_T0LVL); } case OP_REVERSE: /* reverse */ s_return(reverse(car(args))); case OP_APPEND: /* append */ s_return(append(car(args), cadr(args))); case OP_PUT: /* put */ if (!hasprop(car(args)) || !hasprop(cadr(args))) { Error_0("Illegal use of put"); } for (x = symprop(car(args)), y = cadr(args); x != NIL; x = cdr(x)) if (caar(x) == y) break; if (x != NIL) cdar(x) = caddr(args); else symprop(car(args)) = cons(cons(y, caddr(args)), symprop(car(args))); s_return(T); case OP_GET: /* get */ if (!hasprop(car(args)) || !hasprop(cadr(args))) { Error_0("Illegal use of get"); } for (x = symprop(car(args)), y = cadr(args); x != NIL; x = cdr(x)) if (caar(x) == y) break; if (x != NIL) { s_return(cdar(x)); } else { s_return(NIL); } case OP_QUIT: /* quit */ return (NIL); case OP_GC: /* gc */ gc(NIL, NIL); s_return(T); case OP_GCVERB: /* gc-verbose */ { int was = gc_verbose; gc_verbose = (car(args) != F); s_retbool(was); } case OP_NEWSEGMENT: /* new-segment */ if (!isnumber(car(args))) { Error_0("new-segment -- argument must be number"); } fprintf(outfp, "allocate %d new segments\n", alloc_cellseg((int) ivalue(car(args)))); s_return(T); } } pointer opexe_5(op) register short op; { register pointer x, y; switch (op) { /* ========== reading part ========== */ case OP_RDSEXPR: switch (tok) { case TOK_COMMENT: while (inchar() != '\n') ; tok = token(); s_goto(OP_RDSEXPR); case TOK_LPAREN: tok = token(); if (tok == TOK_RPAREN) { s_return(NIL); } else if (tok == TOK_DOT) { Error_0("syntax error -- illegal dot expression"); } else { s_save(OP_RDLIST, NIL, NIL); s_goto(OP_RDSEXPR); } case TOK_QUOTE: s_save(OP_RDQUOTE, NIL, NIL); tok = token(); s_goto(OP_RDSEXPR); #ifdef USE_QQUOTE case TOK_BQUOTE: s_save(OP_RDQQUOTE, NIL, NIL); tok = token(); s_goto(OP_RDSEXPR); case TOK_COMMA: s_save(OP_RDUNQUOTE, NIL, NIL); tok = token(); s_goto(OP_RDSEXPR); case TOK_ATMARK: s_save(OP_RDUQTSP, NIL, NIL); tok = token(); s_goto(OP_RDSEXPR); #endif case TOK_ATOM: s_return(mk_atom(readstr("();\t\n "))); case TOK_DQUOTE: s_return(mk_string(readstrexp())); case TOK_SHARP: if ((x = mk_const(readstr("();\t\n "))) == NIL) { Error_0("Undefined sharp expression"); } else { s_return(x); } default: Error_0("syntax error -- illegal token"); } break; case OP_RDLIST: args = cons(value, args); tok = token(); if (tok == TOK_COMMENT) { while (inchar() != '\n') ; tok = token(); } if (tok == TOK_RPAREN) { s_return(non_alloc_rev(NIL, args)); } else if (tok == TOK_DOT) { s_save(OP_RDDOT, args, NIL); tok = token(); s_goto(OP_RDSEXPR); } else { s_save(OP_RDLIST, args, NIL);; s_goto(OP_RDSEXPR); } case OP_RDDOT: if (token() != TOK_RPAREN) { Error_0("syntax error -- illegal dot expression"); } else { s_return(non_alloc_rev(value, args)); } case OP_RDQUOTE: s_return(cons(QUOTE, cons(value, NIL))); #ifdef USE_QQUOTE case OP_RDQQUOTE: s_return(cons(QQUOTE, cons(value, NIL))); case OP_RDUNQUOTE: s_return(cons(UNQUOTE, cons(value, NIL))); case OP_RDUQTSP: s_return(cons(UNQUOTESP, cons(value, NIL))); #endif /* ========== printing part ========== */ case OP_P0LIST: if (!ispair(args)) { printatom(args, print_flag); s_return(T); } else if (car(args) == QUOTE && ok_abbrev(cdr(args))) { fprintf(outfp, "'"); args = cadr(args); s_goto(OP_P0LIST); #ifdef USE_QQUOTE } else if (car(args) == QQUOTE && ok_abbrev(cdr(args))) { fprintf(outfp, "`"); args = cadr(args); s_goto(OP_P0LIST); } else if (car(args) == UNQUOTE && ok_abbrev(cdr(args))) { fprintf(outfp, ","); args = cadr(args); s_goto(OP_P0LIST); } else if (car(args) == UNQUOTESP && ok_abbrev(cdr(args))) { fprintf(outfp, ",@"); args = cadr(args); s_goto(OP_P0LIST); #endif } else { fprintf(outfp, "("); s_save(OP_P1LIST, cdr(args), NIL); args = car(args); s_goto(OP_P0LIST); } case OP_P1LIST: if (ispair(args)) { s_save(OP_P1LIST, cdr(args), NIL); fprintf(outfp, " "); args = car(args); s_goto(OP_P0LIST); } else { if (args != NIL) { fprintf(outfp, " . "); printatom(args, print_flag); } fprintf(outfp, ")"); s_return(T); } default: sprintf(strbuff, "%d is illegal operator", operator); Error_0(strbuff); } return T; } pointer opexe_6(op) register short op; { register pointer x, y; register long v; static long w; char buffer[32]; switch (op) { case OP_LIST_LENGTH: /* list-length */ /* a.k */ for (x = car(args), v = 0; ispair(x); x = cdr(x)) ++v; s_return(mk_number(v)); case OP_ASSQ: /* assq */ /* a.k */ x = car(args); for (y = cadr(args); ispair(y); y = cdr(y)) { if (!ispair(car(y))) { Error_0("Unable to handle non pair element"); } if (x == caar(y)) break; } if (ispair(y)) { s_return(car(y)); } else { s_return(F); } case OP_PRINT_WIDTH: /* print-width */ /* a.k */ w = 0; args = car(args); print_flag = -1; s_goto(OP_P0_WIDTH); case OP_P0_WIDTH: if (!ispair(args)) { w += printatom(args, print_flag); s_return(mk_number(w)); } else if (car(args) == QUOTE && ok_abbrev(cdr(args))) { ++w; args = cadr(args); s_goto(OP_P0_WIDTH); #ifdef USE_QQUOTE } else if (car(args) == QQUOTE && ok_abbrev(cdr(args))) { ++w; args = cadr(args); s_goto(OP_P0_WIDTH); } else if (car(args) == UNQUOTE && ok_abbrev(cdr(args))) { ++w; args = cadr(args); s_goto(OP_P0_WIDTH); } else if (car(args) == UNQUOTESP && ok_abbrev(cdr(args))) { w += 2; args = cadr(args); s_goto(OP_P0_WIDTH); #endif } else { ++w; s_save(OP_P1_WIDTH, cdr(args), NIL); args = car(args); s_goto(OP_P0_WIDTH); } case OP_P1_WIDTH: if (ispair(args)) { s_save(OP_P1_WIDTH, cdr(args), NIL); ++w; args = car(args); s_goto(OP_P0_WIDTH); } else { if (args != NIL) w += 3 + printatom(args, print_flag); ++w; s_return(mk_number(w)); } case OP_GET_CLOSURE: /* get-closure-code */ /* a.k */ args = car(args); if (args == NIL) { s_return(F); } else if (isclosure(args)) { s_return(cons(LAMBDA, closure_code(value))); #ifdef USE_MACRO } else if (ismacro(args)) { s_return(cons(LAMBDA, closure_code(value))); #endif } else { s_return(F); } case OP_CLOSUREP: /* closure? */ /* * Note, macro object is also a closure. * Therefore, (closure? <#MACRO>) ==> #t */ if (car(args) == NIL) { s_return(F); } s_retbool(isclosure(car(args))); #ifdef USE_MACRO case OP_MACROP: /* macro? */ if (car(args) == NIL) { s_return(F); } s_retbool(ismacro(car(args))); #endif default: sprintf(strbuff, "%d is illegal operator", operator); Error_0(strbuff); } return T; /* NOTREACHED */ } pointer (*dispatch_table[])() = { opexe_0, /* OP_LOAD = 0, */ opexe_0, /* OP_T0LVL, */ opexe_0, /* OP_T1LVL, */ opexe_0, /* OP_READ, */ opexe_0, /* OP_VALUEPRINT, */ opexe_0, /* OP_EVAL, */ opexe_0, /* OP_E0ARGS, */ opexe_0, /* OP_E1ARGS, */ opexe_0, /* OP_APPLY, */ opexe_0, /* OP_DOMACRO, */ opexe_0, /* OP_LAMBDA, */ opexe_0, /* OP_QUOTE, */ opexe_0, /* OP_DEF0, */ opexe_0, /* OP_DEF1, */ opexe_0, /* OP_BEGIN, */ opexe_0, /* OP_IF0, */ opexe_0, /* OP_IF1, */ opexe_0, /* OP_SET0, */ opexe_0, /* OP_SET1, */ opexe_0, /* OP_LET0, */ opexe_0, /* OP_LET1, */ opexe_0, /* OP_LET2, */ opexe_0, /* OP_LET0AST, */ opexe_0, /* OP_LET1AST, */ opexe_0, /* OP_LET2AST, */ opexe_1, /* OP_LET0REC, */ opexe_1, /* OP_LET1REC, */ opexe_1, /* OP_LETREC2, */ opexe_1, /* OP_COND0, */ opexe_1, /* OP_COND1, */ opexe_1, /* OP_DELAY, */ opexe_1, /* OP_AND0, */ opexe_1, /* OP_AND1, */ opexe_1, /* OP_OR0, */ opexe_1, /* OP_OR1, */ opexe_1, /* OP_C0STREAM, */ opexe_1, /* OP_C1STREAM, */ opexe_1, /* OP_0MACRO, */ opexe_1, /* OP_1MACRO, */ opexe_1, /* OP_CASE0, */ opexe_1, /* OP_CASE1, */ opexe_1, /* OP_CASE2, */ opexe_1, /* OP_PEVAL, */ opexe_1, /* OP_PAPPLY, */ opexe_1, /* OP_CONTINUATION, */ opexe_2, /* OP_ADD, */ opexe_2, /* OP_SUB, */ opexe_2, /* OP_MUL, */ opexe_2, /* OP_DIV, */ opexe_2, /* OP_REM, */ opexe_2, /* OP_CAR, */ opexe_2, /* OP_CDR, */ opexe_2, /* OP_CONS, */ opexe_2, /* OP_SETCAR, */ opexe_2, /* OP_SETCDR, */ opexe_3, /* OP_NOT, */ opexe_3, /* OP_BOOL, */ opexe_3, /* OP_NULL, */ opexe_3, /* OP_ZEROP, */ opexe_3, /* OP_POSP, */ opexe_3, /* OP_NEGP, */ opexe_3, /* OP_NEQ, */ opexe_3, /* OP_LESS, */ opexe_3, /* OP_GRE, */ opexe_3, /* OP_LEQ, */ opexe_3, /* OP_GEQ, */ opexe_3, /* OP_SYMBOL, */ opexe_3, /* OP_NUMBER, */ opexe_3, /* OP_STRING, */ opexe_3, /* OP_PROC, */ opexe_3, /* OP_PAIR, */ opexe_3, /* OP_EQ, */ opexe_3, /* OP_EQV, */ opexe_4, /* OP_FORCE, */ opexe_4, /* OP_WRITE, */ opexe_4, /* OP_DISPLAY, */ opexe_4, /* OP_NEWLINE, */ opexe_4, /* OP_ERR0, */ opexe_4, /* OP_ERR1, */ opexe_4, /* OP_REVERSE, */ opexe_4, /* OP_APPEND, */ opexe_4, /* OP_PUT, */ opexe_4, /* OP_GET, */ opexe_4, /* OP_QUIT, */ opexe_4, /* OP_GC, */ opexe_4, /* OP_GCVERB, */ opexe_4, /* OP_NEWSEGMENT, */ opexe_5, /* OP_RDSEXPR, */ opexe_5, /* OP_RDLIST, */ opexe_5, /* OP_RDDOT, */ opexe_5, /* OP_RDQUOTE, */ opexe_5, /* OP_RDQQUOTE, */ opexe_5, /* OP_RDUNQUOTE, */ opexe_5, /* OP_RDUQTSP, */ opexe_5, /* OP_P0LIST, */ opexe_5, /* OP_P1LIST, */ opexe_6, /* OP_LIST_LENGTH, */ opexe_6, /* OP_ASSQ, */ opexe_6, /* OP_PRINT_WIDTH, */ opexe_6, /* OP_P0_WIDTH, */ opexe_6, /* OP_P1_WIDTH, */ opexe_6, /* OP_GET_CLOSURE, */ opexe_6, /* OP_CLOSUREP, */ /* OP_MACROP is kept in to fill in a slot. Will return illegal * operator when macros are disabled. */ opexe_6, /* OP_MACROP, */ opexe_3 /* OP_CHAR */ }; /* kernel of this intepreter */ pointer Eval_Cycle(op) register short op; { operator = op; for (;;) if ((*dispatch_table[operator])(operator) == NIL) return NIL; } /* ========== Initialization of internal keywords ========== */ mk_syntax(op, name) unsigned short op; char *name; { pointer x; x = cons(mk_string(name), NIL); type(x) = (T_SYNTAX | T_SYMBOL); syntaxnum(x) = op; oblist = cons(x, oblist); } mk_proc(op, name) unsigned short op; char *name; { pointer x, y; x = mk_symbol(name); y = get_cell(NIL, NIL); type(y) = (T_PROC | T_ATOM); ivalue(y) = (long) op; car(global_env) = cons(cons(x, y), car(global_env)); } init_vars_global() { pointer x; /* init input/output file */ infp = stdin; outfp = stdout; /* init NIL */ type(NIL) = (T_ATOM | MARK); car(NIL) = cdr(NIL) = NIL; /* init T */ type(T) = (T_ATOM | MARK); car(T) = cdr(T) = T; /* init F */ type(F) = (T_ATOM | MARK); car(F) = cdr(F) = F; /* init global_env */ global_env = cons(NIL, NIL); /* init else */ x = mk_symbol("else"); car(global_env) = cons(cons(x, T), car(global_env)); } init_syntax() { /* init syntax */ mk_syntax(OP_LAMBDA, "lambda"); mk_syntax(OP_QUOTE, "quote"); mk_syntax(OP_DEF0, "define"); mk_syntax(OP_IF0, "if"); mk_syntax(OP_BEGIN, "begin"); mk_syntax(OP_SET0, "set!"); mk_syntax(OP_LET0, "let"); mk_syntax(OP_LET0AST, "let*"); mk_syntax(OP_LET0REC, "letrec"); mk_syntax(OP_COND0, "cond"); mk_syntax(OP_DELAY, "delay"); mk_syntax(OP_AND0, "and"); mk_syntax(OP_OR0, "or"); mk_syntax(OP_C0STREAM, "cons-stream"); #ifdef USE_MACRO mk_syntax(OP_0MACRO, "macro"); #endif mk_syntax(OP_CASE0, "case"); } init_procs() { /* init procedure */ mk_proc(OP_PEVAL, "eval"); mk_proc(OP_PAPPLY, "apply"); mk_proc(OP_CONTINUATION, "call-with-current-continuation"); mk_proc(OP_FORCE, "force"); mk_proc(OP_CAR, "car"); mk_proc(OP_CDR, "cdr"); mk_proc(OP_CONS, "cons"); mk_proc(OP_SETCAR, "set-car!"); mk_proc(OP_SETCDR, "set-cdr!"); mk_proc(OP_ADD, "+"); mk_proc(OP_SUB, "-"); mk_proc(OP_MUL, "*"); mk_proc(OP_DIV, "/"); mk_proc(OP_REM, "remainder"); mk_proc(OP_NOT, "not"); mk_proc(OP_BOOL, "boolean?"); mk_proc(OP_SYMBOL, "symbol?"); mk_proc(OP_NUMBER, "number?"); mk_proc(OP_STRING, "string?"); mk_proc(OP_PROC, "procedure?"); mk_proc(OP_PAIR, "pair?"); mk_proc(OP_EQV, "eqv?"); mk_proc(OP_EQ, "eq?"); mk_proc(OP_NULL, "null?"); mk_proc(OP_ZEROP, "zero?"); mk_proc(OP_POSP, "positive?"); mk_proc(OP_NEGP, "negative?"); mk_proc(OP_NEQ, "="); mk_proc(OP_LESS, "<"); mk_proc(OP_GRE, ">"); mk_proc(OP_LEQ, "<="); mk_proc(OP_GEQ, ">="); mk_proc(OP_READ, "read"); mk_proc(OP_WRITE, "write"); mk_proc(OP_DISPLAY, "display"); mk_proc(OP_NEWLINE, "newline"); mk_proc(OP_LOAD, "load"); mk_proc(OP_ERR0, "error"); mk_proc(OP_REVERSE, "reverse"); mk_proc(OP_APPEND, "append"); mk_proc(OP_PUT, "put"); mk_proc(OP_GET, "get"); mk_proc(OP_GC, "gc"); mk_proc(OP_GCVERB, "gc-verbose"); mk_proc(OP_NEWSEGMENT, "new-segment"); mk_proc(OP_LIST_LENGTH, "list-length"); /* a.k */ mk_proc(OP_ASSQ, "assq"); /* a.k */ mk_proc(OP_PRINT_WIDTH, "print-width"); /* a.k */ mk_proc(OP_GET_CLOSURE, "get-closure-code"); /* a.k */ mk_proc(OP_CLOSUREP, "closure?"); /* a.k */ #ifdef USE_MACRO mk_proc(OP_MACROP, "macro?"); /* a.k */ #endif mk_proc(OP_QUIT, "quit"); mk_proc(OP_CHAR, "char?"); } /* initialize several globals */ init_globals() { init_vars_global(); init_syntax(); init_procs(); /* intialization of global pointers to special symbols */ LAMBDA = mk_symbol("lambda"); QUOTE = mk_symbol("quote"); #ifdef USE_QQUOTE QQUOTE = mk_symbol("quasiquote"); UNQUOTE = mk_symbol("unquote"); UNQUOTESP = mk_symbol("unquote-splicing"); #endif } /* ========== Error ========== */ FatalError(fmt, a, b, c) char *fmt, *a, *b, *c; { fprintf(stderr, "Fatal error: "); fprintf(stderr, fmt, a, b, c); fprintf(stderr, "\n"); exit(1); } #ifdef USE_SETJMP Error(fmt, a, b, c) char *fmt, *a, *b, *c; { fprintf(stderr, "Error: "); fprintf(stderr, fmt, a, b, c); fprintf(stderr, "\n"); flushinput(); longjmp(error_jmp, OP_T0LVL); } #endif /* ========== Main ========== */ main() { short op = (short) OP_LOAD; printf(banner); init_scheme(); args = cons(mk_string(InitFile), NIL); #ifdef USE_SETJMP op = setjmp(error_jmp); #endif Eval_Cycle(op); }