Merge remote-tracking branch 'upstream/master' into d6/binary

README.md

@@ -17,6 +17,7 @@ bin/modal examples/hello.modal
 	-v Print version
 	-q Quiet mode, no step printing
 	-p Print summary with refs count
+	-a Allow files to be imported
 	-n Infinite mode, no rewrites limit
 ```
 

examples/binary.modal

@@ -0,0 +1,10 @@
+?(?: ?:) \#48
+?(?: ?:) \#65
+?(?: ?:) \#6c
+?(?: ?:) \#6c
+?(?: ?:) \#6f
+?(?: ?:) \#0a
+
+?(?: ?:) \#ce\#bb\#0a
+?(?: ?:) \#e9\#ad\#91\#e9\#ad\#85\#e9\#ad\#8d\#e9\#ad\#8e\#0a
+?((?: ?0 ?1) ?:) + #34 #67

examples/file.modal

@@ -0,0 +1,4 @@
+<> (?_ import) (?(?: ?:) (?_ \n) )
+
+(examples/import.modal import)
+(examples/missing.modal import)

examples/import.modal

@@ -0,0 +1 @@
+(this (file (gets (imported by file.modal))))

examples/lisp.modal

@@ -0,0 +1,22 @@
+<> ((defun ?n ?p ?b)) (defun ?n ?p ?b)
+<> (defun ?n ?p ?b) (<> (?n ?p) ?b)
+<> (q ?x) (q ?x)
+<> ((unwrap ?x)) (unwrap ?x)
+<> (unwrap ((?x))) (unwrap (?x))
+<> (unwrap ?x) ?x
+<> (if ?c ?t ?f) (if/q ?c q ?t q ?f)
+<> (if/q (true) q ?t q ?f) (unwrap ?t)
+<> (if/q (false) q ?t q ?f) (unwrap ?f)
+<> (== (?x) (?x)) (true)
+<> (== (?x) (?y)) (false)
+<> (math ?: ?0 ?1) ?:
+<> (+ (?x) (?y)) (math + ?x ?y)
+<> (- (?x) (?y)) (math - ?x ?y)
+<> (* (?x) (?y)) (math * ?x ?y)
+
+(defun factorial (?n)
+  (if (== (?n) (1))
+    (?n)
+    (* (?n) (factorial (- (?n) (1))))))
+
+(factorial (5))

examples/mandelbrot.modal

@@ -0,0 +1,33 @@
+<> (iterating ?x ?y (100) ?z  ?a ?b) (?((?:) ?:) *\s)
+<> (iterating ?x ?y ?n    (1) ?a ?b) (?((?:) ?:) \s\s)
+
+<> (iterating (?x) (?y) (?n) (?c) (?a) (?b)) (
+    iterating (?x) (?y) (?n 1 `+) (?a ?a f* ?b ?b f* `+ 4096 `>) 
+                                  (?a ?a f* ?b ?b f* `- ?x `+) 
+                                  (?a ?b 2048 f* f* ?y `+)
+)
+
+
+<> (?0 ?1 f*) (?0 ?1 `* 1024 `/)
+<> (?0 ?1 f/) (?0 1024 `* ?1 `/)
+<> (?0 ?1 `?:) ?:
+
+<> (mandelbrot (?x) (?y)) (
+    plot-mandelbrot (0) (0) (2529 ?x `/) (2293 ?y `/) (-2048) (-1146)
+)
+
+<> (plot-mandelbrot (40) (36) (?r) (?d) (?x) (?y)) ()
+
+<> (plot-mandelbrot (40) (?j) (?r) (?d) (?x) (?y)) (
+    ?(?: ?:) \n 
+    iterating (?x) (?y) (0) (0) (0) (0)
+    plot-mandelbrot (0) (?j 1 `+) (?r) (?d) (-2048) (?y ?d `+)
+)
+
+<> (plot-mandelbrot (?i) (?j) (?r) (?d) (?x) (?y)) ( 
+    iterating (?x) (?y) (0) (0) (0) (0)
+    plot-mandelbrot (?i 1 `+) (?j) (?r) (?d) (?x ?r `+) (?y)
+)
+
+
+mandelbrot (40) (36)

examples/repl.modal

@@ -1,8 +0,0 @@
-?(?-) (This is a fully functional Modal REPL.)
-
-<> quit EOF
-<> wait?~ (?~ wait!)
-<> (?: print) ?:
-<> (EOF wait!) (Bye.\n print)
-
-(Say something, or type "quit":\n) print wait!

examples/rules.modal

@@ -0,0 +1,19 @@
+<> rule0 data
+<> rule1 data-1
+<> rule2 
+<> rule3 data-10
+<> rule4 data-100
+
+?(?-) (Undefine an empty rule)
+
+>< rule2
+
+?(?-) (Undefine the last rule)
+
+>< rule4
+
+?(?-) (Undefine a non-existant rule)
+
+>< rule5
+
+a sample program

examples/tests.modal

@@ -2,81 +2,137 @@
 
 ?(?-) (Early Test Primitives)
 
-<> (?x = ?x ?n test) (?(?: ?:) (#pass ?n\n))
+<> (?x = ?x ?n test) (?(?: ?:) (pass ?n\n))
 
 <> (ghost) ()
 
 ?(?-) (Formatter)
 
-?((?x ?y) two) aaa(bbb) = two (formatter 1) test
+?((aaa (bbb)) ok) aaa(bbb) = ok (formatter 1/6) test
-?((?x ?y) two) (bbb)aaa = two (formatter 2) test
+?(((bbb) aaa) ok) (bbb)aaa = ok (formatter 2/6) test
-(a b c ) = (a b c) (formatter 3) test
+?(((?a ?b ?c)) ((?a ?b ?c))) (a b c ) = (a b c) (formatter 3/6) test
-( a b c) = (a b c) (formatter 4) test
+?(((?a ?b ?c)) ((?a ?b ?c))) ( a b c) = (a b c) (formatter 4/6) test
-(  a  b  c  ) = (a b c) (formatter 5) test
+?(((?a ?b ?c)) ((?a ?b ?c))) (  a  b  c  ) = (a b c) (formatter 5/6) test
-(a b c  ( a b c )  ) = (a b c (a b c)) (formatter 6) test
+?(((?a ?b ?c (?d ?e ?f))) ((?a ?b ?c (?d ?e ?f)))) (a b c  ( a b c )  ) = (a b c (a b c)) (formatter 6/6) test
 
 ?(?-) (Empty replacements)
 
-(ab cd () ghost) = (ab cd ()) (empty 1) test
+(ab cd () ghost) = (ab cd ()) (empty 1/10) test
-(ab cd ghost ()) = (ab cd ()) (empty 2) test
+(ab cd ghost ()) = (ab cd ()) (empty 2/10) test
-(ab ghost cd ()) = (ab cd ()) (empty 3) test
+(ab ghost cd ()) = (ab cd ()) (empty 3/10) test
-(ghost ab cd ()) = (ab cd ()) (empty 4) test
+(ghost ab cd ()) = (ab cd ()) (empty 4/10) test
-(ghost) = () (empty 5) test
+(ghost) = () (empty 5/10) test
-
+(q ?((?x ?y ?z) (?x ?y)) a b c) = (q a b) (empty 6/10) test
-(q ?((?x ?y ?z) (?x ?y)) a b c) = (q a b) (empty 6) test
+(q ?((?x ?y ?z) (?x ?z)) a b c) = (q a c) (empty 7/10) test
-(q ?((?x ?y ?z) (?x ?z)) a b c) = (q a c) (empty 7) test
+(q ?((?x ?y ?z) (?y ?z)) a b c) = (q b c) (empty 8/10) test
-(q ?((?x ?y ?z) (?y ?z)) a b c) = (q b c) (empty 8) test
 
 <> (prefix/pop ?x) ()
 <> (?x suffix/pop) ()
 
-(ab prefix/pop cd ef) = (ab ef) (empty 9) test
+(ab prefix/pop cd ef) = (ab ef) (empty 9/10) test
-(ab cd suffix/pop ef) = (ab ef) (empty 10) test
+(ab cd suffix/pop ef) = (ab ef) (empty 10/10) test
 
 ?(?-) (Basic register setups)
 
 <> (dup (?x)) (?x ?x)
 <> (swap (?x ?y)) (?y ?x)
-<> (compare (?x ?x ?x)) (#t)
+<> (compare (?x ?x ?x)) (@t)
+<> (compare (?x ?y ?z)) (@f)
 <> (rotate (?x (?y (?z)))) (?y (?z (?x)))
 <> (unused ?x) ?y
 
-(dup (abc)) = (abc abc) (basic 1) test
+(dup (abc)) = (abc abc) (basic 1/6) test
-(swap (abc def)) = (def abc) (basic 2) test
+(swap (abc def)) = (def abc) (basic 2/6) test
-(compare (abc abc abc)) = (#t) (basic 3) test
+(compare (abc abc abc)) = (@t) (basic 3/6) test
-(rotate (abc (def (ghi)))) = (def (ghi (abc))) (basic 4) test
+(compare (abc abc def)) = (@f) (basic 4/6) test
-(unused hey) = (?y) (basic 5) test
+(rotate (abc (def (ghi)))) = (def (ghi (abc))) (basic 5/6) test
+(unused hey) = (?y) (basic 6/6) test
 
 ?(?-) (Substring registers)
 
 <> (connect ?x ?y ?z) (?x-?y?z)
 <> (prefix-?x) (?x-suffix)
 
-connect foo bar baz = foo-barbaz (substring 1) test
+connect foo bar baz = foo-barbaz (substring 1/3) test
-prefix-anything = anything-suffix (substring 2) test
+prefix-anything = anything-suffix (substring 2/3) test
-?(foo QQQ) foobar = foobar (substring 3) test
+?(foo QQQ) foobar = foobar (substring 3/3) test
 
 ?(?-) (Lambdas)
 
-(?(?x (?x ?x)) abc) = (abc abc) (lambda 1) test
+(?(?x (?x ?x)) abc) = (abc abc) (lambda 1/2) test
-abc ?(?x) def = abc (lambda 2) test
+abc ?(?x) def = abc (lambda 2/2) test
 
 ?(?-) (op: explode)
 
-(?(?* ?*) cow) = (c (o (w ()))) (explode word) test
+(?(?* ?*) cow) = (c (o (w ()))) (explode word 1/3) test
-(?(?* ?*) (12 34 45)) = (12 (34 (45 ()))) (explode tuple) test
+(?(?* ?*) (12 34 45)) = (12 (34 (45 ()))) (explode tuple 2/3) test
-(?(?* ?*) ()) = () (explode empty) test
+(?(?* ?*) ()) = () (explode empty 3/3) test
 
 ?(?-) (op: join)
 
-?(?^ ?^) (b (a (t ()))) = bat (join 1) test
+?(?^ ?^) (b (a (t ()))) = bat (join 1/3) test
-?(?^ ?^) (12 (34 (56 ()))) = 123456 (join 2) test
+?(?^ ?^) (12 (34 (56 ()))) = 123456 (join 2/3) test
-(?(?^ ?^) ()) = () (join empty) test
+(?(?^ ?^) ()) = () (join 3/3) test
 
 ?(?-) (op: unwrap)
 
-?(?. ?.) (abcd) = abcd (unwrap 1) test
+?(?. ?.) (abcd) = abcd (unwrap 1/2) test
-(?(?. ?.) ()) = () (unwrap empty) test
+(?(?. ?.) ()) = () (unwrap 2/2) test
+
+?(?-) (Incomplete definitions)
+
+<> (incomplete-basic) ()
+<> (incomplete-reg ?x) ()
+<> () ()
+
+(incomplete-basic) = () (incomplete 1/4) test
+(incomplete-reg abcdef) = () (incomplete 2/4) test
+(?(?x) incomplete-lambda) = () (incomplete 3/4) test
+(?() abc) = (abc) (incomplete 4/4) test
+
+?(?-) (Inline rules)
+
+<> ((?x -> ?y)) (<> ?x ?y)
+(nap -> (tap =))
+nap tap (inline 1/2) test
+
+<> (?x -> ?y) (<> ?x ?y)
+fruit_a -> apple
+fruit_b -> banana
+(apple banana) -> (fruit-salad)
+
+(fruit_a fruit_b) = (fruit-salad) (inline 2/2) test
+
+?(?-) (Undefinition)
+
+<> (undefine-me) (abc)
+<> (undefine-me) (def)
+<> (undefine-me) (ghi)
+>< (undefine-me)
+
+(undefine-me) = (def) (undefinition 1/3) test
+
+>< (undefine-me)
+
+(undefine-me) = (ghi) (undefinition 2/3) test
+
+>< (undefine-unknown)
+
+?(* (>< (undefine-me))) *
+
+(undefine-me) = (undefine-me) (undefinition 3/3) test
+
+?(?-) (Arithmetic)
+
+?((?: ?0 ?1 ?2) ?:) + 1 2 3 = 6 (Arithmetic 1/6) test
+?((?0 ?: ?1) ?:) 16 - 8 = 8 (Arithmetic 2/6) test
+?((?0 ?1 ?:) ?:) 12 10 * = 120 (Arithmetic 3/6) test
+
+<> (?0 ?1 `?:) (?:)
+
+(12 45 `+ -2 `+) = (55) (Arithmetic 4/6) test
+(#12 45 `+ -2 `+) = (#3d) (Arithmetic 5/6) test
+(12 #45 `+ -2 `+) = (79) (Arithmetic 6/6) test
 
 ?(?-) (List reversal)
 
@@ -86,56 +142,7 @@ abc ?(?x) def = abc (lambda 2) test
 
 reverse (modal) = ladom (reverse 1) test
 
-?(?-) (Incomplete definitions)
-
-<> <>
-<> () ()
-<> (incomplete-basic)
-<> (incomplete-reg ?x)
-<> (waste-rule) *
-
-(incomplete-basic) = () (incomplete 1) test
-(incomplete-reg abcdef) = () (incomplete 2) test
-(?(?x) incomplete-lambda) = () (incomplete 3) test
-(?() abc) = (abc) (incomplete 4) test
-
-?(?-) (Inline rules)
-
-<> ((?x -> ?y)) (<> ?x ?y)
-(nap -> (tap =))
-
-nap tap (inline 1) test
-
-?(?-) (Undefinition)
-
-<> (undefine-me) (abc)
-<> (undefine-me) (def)
-<> (undefine-me) (ghi)
->< (undefine-me)
-
-(undefine-me) = (def) (undefinition 1) test
-
->< (undefine-me)
-
-(undefine-me) = (ghi) (undefinition 2) test
-
->< (undefine-unknown)
-
-?(* (>< (undefine-me))) *
-
-(undefine-me) = (undefine-me) (undefinition 3) test
-
-?(?-) (Arithmetic)
-
-?((?: ?0 ?1 ?2) ?:) + 1 2 3 = 6 (Arithmetic 1) test
-?((?0 ?: ?1) ?:) 16 - 8 = 8 (Arithmetic 2) test
-?((?0 ?1 ?:) ?:) 12 10 * = 120 (Arithmetic 3) test
-
-<> (?0 ?1 `?:) (?:)
-
-(12 45 `+ -2 `+) = (55) (Arithmetic 4) test
-
 ?(?-) (Late Test Primitives)
 
-<> (?x = ?y ?n test) (?(?: ?:) (#fail ?n found: ?x expect: ?y\n))
+<> (?x = ?y ?n test) (?(?: ?:) (fail ?n found: ?x, expects: ?y\n))
 

examples/unicode.modal

@@ -0,0 +1,6 @@
+<> (🯅 (?x)) (🯅)
+<> (🯅 🯉) (🯉 🯅 (hey!)) 
+<> (?x 🯉) (🯉 ?x)
+<> (🯅 ?x) (?x 🯅) 
+
+🯅 _ _ _ 🯉

makefile

@@ -8,14 +8,14 @@ all: dest
 dest:
 	@ mkdir -p bin
 run: all bin/modal
-	@ bin/modal -q examples/hello.modal
+	@ bin/modal src/repl.modal
 debug: all bin/modal-debug
-	@ bin/modal-debug examples/hello.modal
+	@ bin/modal-debug examples/rules.modal
 test: all bin/modal-debug bin/modal
 	@ bin/modal -v
 	@ bin/modal-debug -q examples/fizzbuzz.modal
 	@ bin/modal-debug -q examples/sierpinski.modal
-	@ bin/modal-debug -q examples/tests.modal
+	@ bin/modal-debug -q -a examples/tests.modal
 install: bin/modal
 	cp bin/modal ~/bin/
 uninstall:

src/modal.c

@@ -9,14 +9,22 @@ typedef struct {
 	char *a, *b;
 } Rule;
 
-static int flip, quiet, unused, debug, cycles = 0x10000;
+static int flip, quiet, debug, access, cycles = 0x200000;
-static Rule rules[RULES], *rules_ = rules, lambda;
+static Rule rules[0x2000], *rules_ = rules;
-static char dict[DICT], *dict_ = dict, empty;
+static char dict[0x10000], *dict_ = dict;
-static char bank_a[BANK], *src_ = bank_a;
+static char bank_a[0x8000], *src_ = bank_a;
-static char bank_b[BANK], *dst_ = bank_b;
+static char bank_b[0x8000], *dst_ = bank_b;
 static char *regs[0x100], stack[0x10], *stack_ = stack;
 
 #define spacer(c) (c <= ' ' || c == '(' || c == ')')
+#define chex(c) (0xf & (c - (c <= '9' ? '0' : 0x57)))
+
+static char *
+copy(char *src, char *dst, int length)
+{
+	while(length--) *dst++ = *src++;
+	return dst;
+}
 
 static char *
 walk(char *s)
@@ -37,22 +45,27 @@ walk(char *s)
 static int
 sint(char *s)
 {
-	char c;
+	char c = *s, *cap = walk(s);
 	int r = 0, n = 1;
-	if(*s == '-') { n = -1, s++; }
+	if(c == '#') {
-	while((c = *s++) && !spacer(c)) r = r * 10 + c - '0';
+		s++;
+		while((c = *s) && s++ < cap) r = (r << 4) | chex(c);
+		return r;
+	}
+	if(c == '-') { n = -1, s++; }
+	while((c = *s) && s++ < cap) r = r * 10 + c - '0';
 	return r * n;
 }
 
 static void
 device_write(char *s)
 {
-	char c = *s, *cap = walk(s), **reg = regs + '0';
+	char **reg = regs + '0';
 	/* phase: ALU */
 	if(*reg) {
-		int acc = sint(*reg++);
+		int hex = **reg == '#', acc = sint(*reg++);
 		/* clang-format off */
-		switch(c) {
+		switch(*s) {
 		case '+': while(*reg) acc += sint(*reg++); break;
 		case '-': while(*reg) acc -= sint(*reg++); break;
 		case '*': while(*reg) acc *= sint(*reg++); break;
@@ -67,76 +80,107 @@ device_write(char *s)
 		case '<': while(*reg) acc = acc < sint(*reg++); break;
 		}
 		/* clang-format on */
-		dst_ += snprintf(dst_, 0x10, "%d", acc);
+		dst_ += snprintf(dst_, 0x10, hex ? "#%x" : "%d", acc);
 		return;
-	}
+	} else {
 		/* phase: string */
+		char *cap = walk(s);
 		if(*s == '(') s++, --cap;
 		while(s < cap) {
-		c = *s++;
+			char c = *s++, hb, lb;
 			if(c == '\\') {
 				switch(*s++) {
 				case 't': putc(0x09, stdout); break;
 				case 'n': putc(0x0a, stdout); break;
 				case 's': putc(0x20, stdout); break;
+				case '#': hb = *s++, lb = *s++, putc((chex(hb) << 4) | chex(lb), stdout); break;
 				}
 			} else
 				putc(c, stdout);
 		}
+	}
 }
 
-static void
+static char *
-device_read(void)
+file_import(char *path, char *ptr)
 {
-	char c, *origin = dst_;
+	FILE *f;
-	while(fread(&c, 1, 1, stdin) && c >= ' ')
+	int pr = 0;
-		*dst_++ = c;
+	if((f = fopen(path, "r"))) {
-	if(feof(stdin))
+		unsigned char c, last = 0;
-		*dst_++ = 'E', *dst_++ = 'O', *dst_++ = 'F';
+		while(fread(&c, 1, 1, f)) {
-	if(dst_ - origin == 0)
+			c = c <= 0x20 ? 0x20 : c;
-		dst_--;
+			if(c == '(') pr++;
+			if(c == ')') pr--;
+			if(c == ' ' && last == '(') continue;
+			if(c == ')' && last == ' ') ptr--;
+			if(c == ' ' && last == ' ') ptr--;
+			if(c == '(' && last != '?' && !spacer(last)) *ptr++ = ' ';
+			if(last == ')' && !spacer(c)) *ptr++ = ' ';
+			*ptr++ = last = c;
+		}
+		while(*(--ptr) <= ' ') *ptr = 0;
+		fclose(f);
+		if(pr) fprintf(stderr, "Modal program imbalanced.\n");
+		return ptr;
+	}
+	return copy("NAF", ptr, 3);
 }
 
 static void
 write_reg(char r, char *reg)
 {
-	char c, *cap = walk(reg);
 	switch(r) {
-	case ':': device_write(reg); return;
+	case ':': device_write(reg); break;
-	case '~': device_read(); return;
+	case '~': {
-	case '^': /* op: join */
+		unsigned char c;
+		char *origin = dst_;
+		while(fread(&c, 1, 1, stdin) && c >= ' ') *dst_++ = c;
+		if(feof(stdin)) dst_ = copy("EOF", dst_, 3);
+		if(origin == dst_) dst_--;
+		break;
+	}
+	case '_': {
+		char filepath[0x80];
+		copy(reg, filepath, walk(reg) - reg);
+		dst_ = file_import(filepath, dst_);
+		break;
+	}
+	case '^': { /* op: join */
+		char c, *cap = walk(reg);
 		if(*reg == '(') reg++, --cap;
 		while(reg < cap && (c = *reg++))
 			if(!spacer(c)) *dst_++ = c;
-		return;
+		break;
-	case '.': /* op: unwrap */
+	}
+	case '.': { /* op: unwrap */
+		char *cap = walk(reg);
 		if(*reg == '(') reg++, --cap;
-		while(reg < cap) *dst_++ = *reg++;
+		dst_ = copy(reg, dst_, cap - reg);
-		return;
+		break;
+	}
 	case '*': { /* op: explode */
 		int i, depth = 0;
+		char c, *cap = walk(reg);
 		if(*reg == '(' && reg[1] != ')') { /* tuple */
 			reg++;
-			while(reg < cap) {
+			while(reg < cap - 1) {
 				while((c = *reg) && !spacer(c))
 					*dst_++ = c, reg++;
-				*dst_++ = ' ';
+				*dst_++ = ' ', *dst_++ = '(', reg++, depth++;
-				*dst_++ = '(', reg++, depth++;
 			}
 		} else /* token */
 			while((c = *reg++) && !spacer(c))
 				*dst_++ = c, *dst_++ = ' ', *dst_++ = '(', depth++;
 		for(i = 0; i < depth; i++) *dst_++ = ')';
-		return;
+		break;
 	}
-	default:
+	default: dst_ = copy(reg, dst_, walk(reg) - reg);
-		while(reg < cap) *dst_++ = *reg++;
-		return;
 	}
 }
 
 static int
-write_tail(char *s)
+write_tail(char *s, Rule *r)
 {
 	while((*dst_++ = *s++))
 		;
@@ -145,6 +189,7 @@ write_tail(char *s)
 		src_ = bank_b, dst_ = bank_a;
 	else
 		src_ = bank_a, dst_ = bank_b;
+	if(r && !quiet) fprintf(stderr, "%02d %s\n", r->id, src_), ++r->refs;
 	return 1;
 }
 
@@ -173,39 +218,34 @@ apply_rule(Rule *r, char *s)
 	c = *s;
 	if(!spacer(c)) return 0;
 	/* phase: write rule */
-	while((c = *b++)) {
+	while((c = *b++))
-		if(c == '?') {
+		if(c == '?' && (rid = *b) && (reg = regs[rid]))
-			rid = *b;
+			write_reg(rid, reg), b++;
-			if((reg = regs[rid]))
-				b++, write_reg(rid, reg);
 		else
 			*dst_++ = c;
-		} else
-			*dst_++ = c;
-	}
 	if(dst_ == origin) {
 		while(*s == ' ') s++;
 		if(*s == ')' && *(dst_ - 1) == ' ') dst_--;
 	}
-	if(!quiet) fprintf(stderr, "%02d %s\n", r->id, src_), ++r->refs;
+	return write_tail(s, r);
-	return write_tail(s);
 }
 
 static char *
-parse_frag(char **side, char *src)
+parse_frag(char **side, char *s)
 {
-	int wrapped;
 	char c, *cap;
-	while((c = *src) && c == ' ') src++;
+	while((c = *s) && c == ' ') s++;
-	if(c == ')' || (c == '<' && src[1] == '>')) {
+	if(c == ')' || (c == '<' && s[1] == '>') || (c == '>' && s[1] == '<'))
-		*side = &empty;
+		*side = dict_, *dict_++ = 0;
-		return src;
+	else {
+		cap = walk(s), *side = dict_;
+		if(c == '(')
+			dict_ = copy(s + 1, dict_, cap - s - 2);
+		else
+			dict_ = copy(s, dict_, cap - s);
+		s = cap, *dict_++ = 0;
 	}
-	*side = dict_, cap = walk(src), wrapped = c == '(';
+	return s;
-	if(wrapped) src++, cap--;
-	while(src < cap) c = *src, *dict_++ = *src++;
-	src += wrapped, *dict_++ = 0;
-	return src;
 }
 
 static Rule *
@@ -215,7 +255,6 @@ find_rule(char *s, char *cap)
 	if(*s == '(') s++, cap--;
 	while(r < rules_) {
 		char *ss = s, *a = r->a;
-		if(a)
 		while(*ss++ == *a++)
 			if(!*a && ss == cap) return r;
 		r++;
@@ -223,6 +262,24 @@ find_rule(char *s, char *cap)
 	return NULL;
 }
 
+static void
+remove_rule(Rule *r)
+{
+	if(r < rules_ - 1) {
+		char *memsrc = (r + 1)->a;
+		int distance = (r + 1)->a - r->a;
+		copy(memsrc, r->a, dict_ - memsrc);
+		while(r < rules_ - 1) {
+			Rule *next = r + 1;
+			r->id = next->id, r->refs = next->refs;
+			r->a = next->a - distance;
+			r->b = next->b - distance;
+			r++;
+		}
+	}
+	rules_--;
+}
+
 static int
 rewrite(void)
 {
@@ -230,51 +287,47 @@ rewrite(void)
 	while(*s == ' ') s++;
 	while((c = *s)) {
 		if(c == '(' || spacer(last)) {
-			Rule *r = NULL;
+			Rule *r;
 			/* phase: undefine */
 			if(c == '>' && s[1] == '<') {
 				s += 2;
 				while(*s == ' ') s++;
 				cap = walk(s), r = find_rule(s, cap);
 				if(r != NULL) {
-					if(!quiet) fprintf(stderr, ">< (%s) (%s)\n", r->a, r->b);
+					if(!quiet) fprintf(stderr, ">< (%s) (%s)\n", r->a ? r->a : "", r->b ? r->b : "");
-					r->a = 0;
+					remove_rule(r);
 				}
 				while(*cap == ' ') cap++;
-				return write_tail(cap);
+				return write_tail(cap, NULL);
 			}
 			/* phase: define */
 			if(c == '<' && s[1] == '>') {
 				r = rules_, r->id = rules_ - rules;
 				s = parse_frag(&r->b, parse_frag(&r->a, s + 2));
 				if(*r->a) {
-					if(!quiet) fprintf(stderr, "<> (%s) (%s)\n", r->a, r->b);
+					if(!quiet) fprintf(stderr, "<> (%s) (%s)\n", r->a ? r->a : "", r->b ? r->b : "");
 					rules_++;
 				}
 				while(*s == ' ') s++;
-				return write_tail(s);
+				return write_tail(s, NULL);
 			}
 			/* phase: lambda */
 			if(c == '?' && s[1] == '(') {
-				char *d_ = dict_;
+				char *d = dict_;
 				cap = walk(s + 1);
-				r = &lambda, r->id = -1;
+				r = rules_, r->id = -1;
 				parse_frag(&r->b, parse_frag(&r->a, s + 2));
 				s = cap;
 				while(*s == ' ') s++;
-				if(!apply_rule(&lambda, s)) {
+				if(!(*r->a) || !apply_rule(r, s)) write_tail(s, NULL);
-					if(!quiet) fprintf(stderr, "%02d %s\n", r->id, src_), ++r->refs;
+				dict_ = d;
-					write_tail(s);
-				}
-				dict_ = d_;
 				return 1;
 			}
 			/* phase: match */
 			for(r = rules; r < rules_; r++)
-				if(r->a && apply_rule(r, s)) return 1;
+				if(apply_rule(r, s)) return 1;
 		}
-		*dst_++ = last = c;
+		*dst_++ = last = c, s++;
-		s++;
 	}
 	*dst_++ = 0;
 	return 0;
@@ -283,48 +336,26 @@ rewrite(void)
 int
 main(int argc, char **argv)
 {
-	FILE *f;
+	int i, rw = 0;
-	int i, pl = 0, pr = 0, rw = 0;
-	char c, last = 0, *w = bank_a;
 	if(argc < 2)
 		return !printf("usage: modal [-vqn] source.modal\n");
 	for(i = 1; i < argc && *argv[i] == '-'; i++) {
 		switch(argv[i][1]) {
-		case 'v': /* version */ return !printf("Modal Interpreter, 4 May 2024.\n");
+		case 'v': /* version */ return !printf("Modal Interpreter, 24 May 2024.\n");
 		case 'q': /* quiet */ quiet = 1; break;
 		case 'p': /* debug */ debug = 1; break;
+		case 'a': /* access */ access = 1; break;
 		case 'n': /* infinite */ cycles = 0xffffffff; break;
 		case 'u': /* unused */ unused = 1; break;
 		}
 	}
-	if(!(f = fopen(argv[i], "r")))
+	file_import(argv[i], src_);
-		return !printf("Modal file invalid: %s.\n", argv[i]);
-	while(fread(&c, 1, 1, f)) {
-		c = c <= 0x20 ? 0x20 : c;
-		if(c == ' ' && last == '(') continue;
-		if(c == ')' && last == ' ') w--;
-		if(c == ' ' && last == ' ') w--;
-		if(c == '(') pl++;
-		if(c == ')') pr++;
-		if(c == '(' && last != '?' && !spacer(last)) *w++ = ' ';
-		if(last == ')' && !spacer(c)) *w++ = ' ';
-		*w++ = last = c;
-	}
-	while(*(--w) <= ' ') *w = 0;
-	fclose(f);
-	if(pr != pl)
-		return !fprintf(stderr, "Modal program imbalanced.\n");
 	while(rewrite() && ++rw)
 		if(!cycles--) return !fprintf(stderr, "Modal rewrites exceeded.\n");
 	if(!quiet) {
-		while(rules_-- > rules) {
+		while(rules_-- > rules)
-			if(rules_->a) {
+			if(rules_->a && !rules_->refs)
-				if(unused && !rules_->refs)
 				fprintf(stderr, "-- Unused rule: %d <> (%s) (%s)\n", rules_->id, rules_->a, rules_->b);
-				if(debug)
-					fprintf(stderr, "   (%s) (%s), %d times.\n", rules_->a, rules_->b, rules_->refs);
-			}
-		}
 		if(rw)
 			fprintf(stderr, ".. %s\nCompleted in %d rewrites.\n", src_, rw);
 	}

src/repl.modal

@@ -0,0 +1,17 @@
+?(?: ?:) (
+\n
+\t Hi! Welcome to Modal\n
+\t Start rewriting, or type "quit"\n
+\n
+\t <> Define a rule\n
+\t >< Undefine a rule\n
+\t ?x Assign a register\n
+\n
+\t Have fun\n
+\n
+)
+
+<> (quit @.) (?(?: ?:) (\n\t See you soon\n))
+<> @?~ (?~ @.)
+
+@.