shithub: riscv

Info  •  Files  •  Log  •  Branches

games/mix: implement Knuth's specification for comments

--- a/sys/man/1/mix

+++ b/sys/man/1/mix

@@ -92,7 +92,8 @@

 The

 .I addr

 field of the above instructions must be an integer between 0 and 3999

-inclusive. A number-sign (#) starts a comment which extends to the end

+inclusive. A number-sign (#) or an asterisk (*) at the beginning of

+a line starts a comment which extends to the end

 of the line.

 .SH SOURCE

 .B /sys/src/games/mix

@@ -118,4 +119,4 @@

 implemented.

 .PP

 Comments are handled as described above and not

-as Knuth specifies.

+exactly as Knuth specifies.

--- a/sys/src/games/mix/examples/primes.m

+++ b/sys/src/games/mix/examples/primes.m

@@ -1,3 +1,5 @@

+* EXAMPLE PROGRAM ... TABLE OF PRIMES

+*

 L	EQU	500

 PRINTER	EQU	18

 PRIME	EQU	-1

@@ -34,6 +36,7 @@

 	LD4	24,4

 	J5N	2B

 	HLT

+* INITIAL CONTENTS OF TABLES AND BUFFERS

 ORIG	PRIME+1

 	CON	2

 	ORIG	BUF0-5

--- a/sys/src/games/mix/mix.c

+++ b/sys/src/games/mix/mix.c

@@ -298,10 +298,33 @@

 	return fmtprint(f, "%d\t%d,%d(%d | %d:%d)", opc, apart, ipart, fpart, a, b);

 }

+Rune

+getr(void)

+{

+	static int bol = 1;

+	Rune r;

+

+	r = Bgetrune(&bin);

+	switch(r) {

+	case '*':

+		if(!bol)

+			break;

+	case '#':

+		skipto('\n');

+	case '\n':

+		line++;

+		bol = 1;

+		return '\n';

+	}

+	bol = 0;

+	return r;

+}

+

 long

 yylex(void)

 {

 	static Rune buf[11];

+	static int bol;

 	Rune r, *bp, *ep;

 	static char cbuf[100];

 	int isnum;

@@ -310,7 +333,7 @@

 		return -1;

 Loop:

-	r = Bgetrune(&bin);

+	r = getr();

 	switch(r) {

 	case Beof:

 		return -1;

@@ -318,35 +341,32 @@

 	case ' ':

 		goto Loop;

 	case '\n':

-		line++;

+	case '*':

 	case '+':

 	case '-':

-	case '*':

 	case ':':

 	case ',':

 	case '(':

 	case ')':

 	case '=':

+		bol = 0;

 		return r;

 	case '/':

-		r = Bgetrune(&bin);

-		if(r == '/')

+		r = getr();

+		if(r == '/') {

+			bol = 0;

 			return LSS;

-		else

+		} else

 			Bungetrune(&bin);

 		return '/';

 	case '"':

 		for(bp = buf; bp < buf+5; bp++) {

-			*bp = Bgetrune(&bin);

+			*bp = getr();

 		}

-		if(Bgetrune(&bin) != '"')

+		if(getr() != '"')

 			yyerror("Bad string literal\n");

 		yylval.rbuf = buf;

 		return LSTR;

-	case '#':

-		skipto('\n');

-		line++;

-		return '\n';

 	}

 	bp = buf;

 	ep = buf+nelem(buf)-1;

@@ -359,7 +379,7 @@

 		*bp++ = r;

 		if(isnum && (r >= Runeself || !isdigit(r)))

 			isnum = 0;

-		r = Bgetrune(&bin);

+		r = getr();

 		switch(r) {

 		case Beof:

 		case '\t':