stage 4 (incomplete).front

6 files changed, 295 insertions, 0 deletions

diff --git a/s4/builtin.c b/s4/builtin.c
new file mode 100644
index 0000000..e9208cf
--- /dev/null
+++ b/s4/builtin.c
@@ -0,0 +1,46 @@
+#include <u.h>
+#include <libc.h>
+#include "dat.h"
+#include "fns.h"
+#include "y.tab.h"
+
+static Const consts[] = {
+	"π",	3.14159265358979323846,
+	"e",	2.71828182845904523536,
+	"γ",	0.57721566490153286060,
+	"DEG",	57.29577951308232087680,
+	"Φ",	1.61803398874989484820,
+};
+
+static Builtin builtins[] = {
+	"sin",		sin,
+	"cos",		cos,
+	"atan",		atan,
+	"atan2",	atan2,
+	"log",		log,
+	"log10",	log10,
+	"exp",		exp,
+	"sqrt",		sqrt,
+	"int",		round,
+	"abs",		fabs,
+};
+
+double
+round(double n)
+{
+	return floor(n + 0.5);
+}
+
+void
+init(void)
+{
+	Symbol *s;
+	int i;
+
+	for(i = 0; i < nelem(consts); i++)
+		install(consts[i].name, CONST, consts[i].val);
+	for(i = 0; i < nelem(builtins); i++){
+		s = install(builtins[i].name, BLTIN, 0);
+		s->u.fn = builtins[i].fn;
+	}
+}
diff --git a/s4/dat.h b/s4/dat.h
new file mode 100644
index 0000000..9cdb6c7
--- /dev/null
+++ b/s4/dat.h
@@ -0,0 +1,23 @@
+typedef struct Symbol Symbol;
+typedef struct Const Const;
+typedef struct Builtin Builtin;
+
+struct Symbol {
+	char *name;
+	int type;
+	union {
+		double val;
+		double (*fn)(double);
+	} u;
+	Symbol *next;
+};
+
+struct Const {
+	char *name;
+	double val;
+};
+
+struct Builtin {
+	char *name;
+	double (*fn)();
+};
diff --git a/s4/fns.h b/s4/fns.h
new file mode 100644
index 0000000..e868440
--- /dev/null
+++ b/s4/fns.h
@@ -0,0 +1,7 @@
+Symbol *install(char *, int, double);
+Symbol *lookup(char *);
+double round(double);
+void init(void);
+void *emalloc(ulong);
+
+int yyparse(void);
diff --git a/s4/mkfile b/s4/mkfile
new file mode 100644
index 0000000..70aeac7
--- /dev/null
+++ b/s4/mkfile
@@ -0,0 +1,16 @@
+</$objtype/mkfile
+
+TARG=rhoc3
+OFILES=\
+	y.tab.$O\
+	sym.$O\
+	builtin.$O
+YFILES=\
+	rhoc.y
+HFILES=\
+	dat.h\
+	fns.h\
+	y.tab.h
+BIN=/$objtype/bin
+
+</sys/src/cmd/mkone
diff --git a/s4/rhoc.y b/s4/rhoc.y
new file mode 100644
index 0000000..ea62b13
--- /dev/null
+++ b/s4/rhoc.y
@@ -0,0 +1,172 @@
+%{
+#include "dat.h"
+%}
+%union {
+	double val;
+	Symbol *sym;
+}
+%token	<val> NUMBER
+%token	<sym> VAR CONST BLTIN UNDEF
+%type	<val> expr asgn
+%right	'='
+%left	'+' '-'
+%left	'*' '/'
+%left	'%'
+%right	'^'
+%left	UMINUS
+%%
+list:	/* ε */
+	| list '\n'
+	| list asgn '\n'
+	| list expr '\n'	{ print("\t%.8g\n", $2); }
+	| list error '\n'	{ yyerrok; }
+	;
+asgn:	  VAR '=' expr
+	{
+		if($1->type == CONST)
+			rterror("assignment to constant");
+		$$ = $1->u.val = $3;
+		$1->type = VAR;
+	}
+	;
+expr:	  NUMBER
+	| VAR
+	{
+		if($1->type == UNDEF)
+			rterror("undefined variable");
+		$$ = $1->u.val;
+	}
+	| asgn
+	| BLTIN '(' expr ')'	{ $$ = $1->u.fn($3); }
+	| '-' expr	%prec UMINUS { $$ = -$2; }
+	| expr '+' expr		{ $$ = $1 + $3; }
+	| expr '-' expr 	{ $$ = $1 - $3; }
+	| expr '*' expr 	{ $$ = $1 * $3; }
+	| expr '/' expr
+	{
+		if($3 == 0)
+			rterror("division by zero");
+		$$ = $1 / $3;
+	}
+	| expr '%' expr 	{ $$ = fmod($1, $3); }
+	| expr '^' expr 	{ $$ = pow($1, $3); }
+	| expr '(' expr ')'	{ $$ = $1 * $3; }
+	| '(' expr ')'		{ $$ = $2; }
+	;
+%%
+#include <u.h>
+#include <libc.h>
+#include <ctype.h>
+#include <bio.h>
+#include "fns.h"
+
+Biobuf *bin;
+jmp_buf begin;
+int lineno;
+int prompt;
+
+void *
+emalloc(ulong n)
+{
+	void *p;
+
+	p = malloc(n);
+	if(p == nil)
+		sysfatal("malloc: %r");
+	memset(p, 0, n);
+	setmalloctag(p, getcallerpc(&n));
+	return p;
+}
+
+void
+yyerror(char *msg)
+{
+	fprint(2, "%s at line %d\n", msg, lineno);
+}
+
+void
+rterror(char *msg)
+{
+	fprint(2, "%s at line %d\n", msg, lineno-1);
+	longjmp(begin, 0);
+}
+
+int
+catch(void *ureg, char *msg)
+{
+	if(strncmp(msg, "sys: fp", 7) == 0){
+		yyerror("floating point exception");
+		notejmp(ureg, begin, 0);
+	}
+	return 0;
+}
+
+int
+yylex(void)
+{
+	Symbol *s;
+	char sname[256], *p;
+	Rune r;
+
+	if(prompt){
+		print("%d: ", lineno);
+		prompt--;
+	}
+	while((r = Bgetrune(bin)) == ' ' || r == '\t')
+		;
+	if(r == Beof)
+		return 0;
+	if(r == '.' || isdigitrune(r)){
+		Bungetrune(bin);
+		Bgetd(bin, &yylval.val);
+		return NUMBER;
+	}
+	if(isalpharune(r)){
+		p = sname;
+		do{
+			if(p+runelen(r) - sname >= sizeof(sname))
+				return r; /* force syntax error. */
+			p += runetochar(p, &r);
+		}while((r = Bgetrune(bin)) != Beof &&
+			(isalpharune(r) || isdigitrune(r)));
+		Bungetrune(bin);
+		*p = 0;
+		if((s = lookup(sname)) == nil)
+			s = install(sname, UNDEF, 0);
+		yylval.sym = s;
+		return s->type == UNDEF || s->type == CONST ? VAR : s->type;
+	}
+	if(r == '\n'){
+		lineno++;
+		prompt++;
+	}
+	return r;
+}
+
+void
+usage(void)
+{
+	fprint(2, "usage: %s\n", argv0);
+	exits("usage");
+}
+
+void
+main(int argc, char *argv[])
+{
+	ARGBEGIN{
+	default: usage();
+	}ARGEND;
+	if(argc > 0)
+		usage();
+	atnotify(catch, 1);
+	bin = Bfdopen(0, OREAD);
+	if(bin == nil)
+		sysfatal("Bfdopen: %r");
+	lineno++;
+	prompt++;
+	init();
+	setjmp(begin);
+	yyparse();
+	Bterm(bin);
+	exits(0);
+}
diff --git a/s4/sym.c b/s4/sym.c
new file mode 100644
index 0000000..8749791
--- /dev/null
+++ b/s4/sym.c
@@ -0,0 +1,31 @@
+#include <u.h>
+#include <libc.h>
+#include "dat.h"
+#include "fns.h"
+
+static Symbol *symtab;
+
+Symbol *
+install(char *s, int t, double v)
+{
+	Symbol *sym;
+
+	sym = emalloc(sizeof(Symbol));
+	sym->name = strdup(s);
+	sym->type = t;
+	sym->u.val = v;
+	sym->next = symtab;
+	symtab = sym;
+	return sym;
+}
+
+Symbol *
+lookup(char *s)
+{
+	Symbol *sym;
+
+	for(sym = symtab; sym != nil; sym = sym->next)
+		if(strcmp(sym->name, s) == 0)
+			return sym;
+	return nil;
+}