listbas: initial support for autodetecting BASIC dialect (-A option).

3 files changed, 83 insertions, 5 deletions

diff --git a/listbas.1 b/listbas.1
index a3c5c4b..37ecd69 100644
--- a/listbas.1
+++ b/listbas.1
@@ -48,6 +48,11 @@ the \fB\-b\fP option for details.
 .SS BASIC options
 .INDENT 0.0
 .TP
+.B \fB\-A\fP
+Autodetect the BASIC dialect. Runs \fBwhichbas\fP(1) as an external
+process, so it must be available on \fB$PATH\fP\&. Someday, this will
+be enabled by default...
+.TP
 .B \fB\-b\fP
 Set the BASIC dialect the program was written in. Choices are:
 .INDENT 7.0
diff --git a/listbas.c b/listbas.c
index bcdb052..d0a87fd 100644
--- a/listbas.c
+++ b/listbas.c
@@ -8,6 +8,8 @@
 #include <math.h>
 #include <errno.h>
 
+#include <sys/wait.h>
+
 #include "bas.h"
 #include "bcdfp.h"
 #include "tokens.h"
@@ -74,6 +76,7 @@ int immediate =   0;  /* 1 with -i */
 int underline =   0;  /* 1 with -u */
 int skip_lineno = 0;  /* 1 with -l */
 int dump_tables = 0;  /* 1 with -D */
+int autodetect  = 0;  /* 1 with -a */
 
 /* change these with -c */
 int color_cmd =       C_YELLOW;
@@ -85,6 +88,8 @@ int color_rem =       C_BLUE;
 int color_data =      C_CYAN;
 int color_varnames  = NO_COLOR;
 
+const char *input_filename;
+
 int badtok =      0; /* set to 1 if we find a bad token */
 int inv =         0; /* set to 1 when we're printing inverse */
 int cur_color =  -1; /* -1 = no color */
@@ -162,14 +167,15 @@ void parse_args(int argc, char **argv, int from_env) {
 
 	optind = 1;
 
-	while( (opt = getopt(argc, argv, "Db:UCviamnBdhxulc:")) != -1) {
+	while( (opt = getopt(argc, argv, "ADb:UCviamnBdhxulc:")) != -1) {
 		switch(opt) {
-			case 'D': dump_tables = 1;         break;
 			case 'U': output_mode = M_UTF8;    break;
 			case 'a': output_mode = M_ATASCII; break;
 			case 'm': output_mode = M_MAG;     break;
 			case 'd': output_mode = M_DOTS;    break;
 			case 'x': output_mode = M_UTF8_I;  break;
+			case 'A': autodetect =  1; break;
+			case 'D': dump_tables = 1; break;
 			case 'v': verbose =     1; break;
 			case 'i': immediate =   1; break;
 			case 'B': bold =        1; break;
@@ -187,10 +193,12 @@ void parse_args(int argc, char **argv, int from_env) {
 	}
 
 	if(!from_env) {
-		if(optind >= argc)
+		if(optind >= argc) {
 			die("No input file given (use - for stdin).");
-		else
-			open_input(argv[optind]);
+		} else {
+			input_filename = argv[optind];
+			open_input(input_filename);
+		}
 	}
 }
 
@@ -705,7 +713,67 @@ void init_token_tables() {
 	}
 }
 
+void set_bas_dialect(int d) {
+	if(verbose)
+		fprintf(stderr, "set_bas_dialect(%d)\n", d);
+
+	switch(d) {
+		case 0:
+		case 1:
+			die("whichbas child process failed");
+			break;
+		case SRET_ATARI:
+		case SRET_APLUS:
+		case SRET_TURBO:
+		case SRET_BXL:
+		case SRET_BXE:
+			bas_type = d;
+			break;
+		default:
+			fprintf(stderr, "whichbas results ambiguous; guessing Turbo BASIC\n");
+			bas_type = SRET_TURBO;
+			break;
+	}
+}
+
+void detect_bas_dialect() {
+	pid_t pid, status;
+	int wstatus;
+	const char *args[4];
+
+	args[0] = "whichbas";
+	args[1] = "-s";
+	args[2] = input_filename;
+	args[3] = 0;
+
+	pid = fork();
+	if(pid == -1) {
+		perror("fork()");
+		die("Can't spawn child process");
+	} else if(pid) {
+		/* we are the parent */
+		status = waitpid(pid, &wstatus, 0);
+		if(status < 0) {
+			perror("waitpid()");
+			die("Child process went south");
+		}
+		if(!WIFEXITED(wstatus)) {
+			die("Child process went south");
+		}
+		set_bas_dialect(WEXITSTATUS(wstatus));
+	} else {
+		/* we are the child */
+		if(execvp(args[0], (char * const *)args) < 0) {
+			perror("exec()");
+			exit(1);
+		}
+	}
+}
+
 void init_bas_dialect() {
+	if(autodetect)
+		detect_bas_dialect();
+
 	if(bas_type == B_BXL || bas_type == B_BXE)
 		allow_hex_const = 1;
 
diff --git a/listbas.rst b/listbas.rst
index a2c0f0f..6b31319 100644
--- a/listbas.rst
+++ b/listbas.rst
@@ -32,6 +32,11 @@ OPTIONS
 BASIC options
 -------------
 
+**-A**
+  Autodetect the BASIC dialect. Runs **whichbas**\(1) as an external
+  process, so it must be available on **$PATH**. Someday, this will
+  be enabled by default...
+
 **-b**
   Set the BASIC dialect the program was written in. Choices are: