main: refactor option parsing and VM setup

Set VM options and environment variables and load modules on the fly
while parsing the cli options instead of aggregating all the values in
memory first.

This vastly reduces the amount of arguments we need to pass to the
parse() function. Also rename parse() to compile() while we're at it.

Also slightly adjust the usage output.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 36 insertions, 61 deletions

diff --git a/main.c b/main.c
index 58ac2b3..58c9826 100644
--- a/main.c
+++ b/main.c
@@ -39,11 +39,11 @@ static void
 print_usage(const char *app)
 {
 	printf(
-	"== Usage ==\n\n"
+	"Usage\n\n"
 	"  # %s [-t] [-l] [-r] [-S] [-R] [-e '[prefix=]{\"var\": ...}'] [-E [prefix=]env.json] {-i <file> | -s \"ucode script...\"}\n"
 	"  -h, --help	Print this help\n"
-	"  -i file	Specify an ucode script to parse\n"
-	"  -s \"ucode script...\"	Specify an ucode fragment to parse\n"
+	"  -i file	Execute the given ucode script file\n"
+	"  -s \"ucode script...\"	Execute the given string as ucode script\n"
 	"  -t Enable VM execution tracing\n"
 	"  -l Do not strip leading block whitespace\n"
 	"  -r Do not trim trailing block newlines\n"
@@ -74,22 +74,14 @@ register_variable(uc_value_t *scope, const char *key, uc_value_t *val)
 
 
 static int
-parse(uc_parse_config_t *config, uc_source_t *src,
-      uc_value_t *env, uc_value_t *modules,
-      int argc, char **argv, int trace)
+compile(uc_vm_t *vm, uc_source_t *src)
 {
-	uc_value_t *globals = NULL, *res = NULL, *arr, *name, *mod;
+	uc_value_t *res = NULL;
 	uc_function_t *entry;
-	uc_vm_t vm = { 0 };
-	int i, rc = 0;
-	size_t idx;
+	int rc = 0;
 	char *err;
 
-	uc_vm_init(&vm, config);
-
-	uc_vm_trace_set(&vm, trace);
-
-	entry = uc_compile(config, src, &err);
+	entry = uc_compile(vm->config, src, &err);
 
 	if (!entry) {
 		fprintf(stderr, "%s", err);
@@ -98,36 +90,7 @@ parse(uc_parse_config_t *config, uc_source_t *src,
 		goto out;
 	}
 
-	/* allocate global scope */
-	globals = uc_vm_scope_get(&vm);
-
-	/* register ARGV array */
-	arr = ucv_array_new_length(&vm, argc);
-
-	for (i = 0; i < argc; i++)
-		ucv_array_push(arr, ucv_string_new(argv[i]));
-
-	ucv_object_add(globals, "ARGV", arr);
-
-	/* load env variables */
-	if (env) {
-		ucv_object_foreach(env, key, val)
-			register_variable(globals, key, ucv_get(val));
-	}
-
-	/* load std functions into global scope */
-	uc_load_stdlib(globals);
-
-	/* preload modules */
-	for (idx = 0; idx < ucv_array_length(modules); idx++) {
-		name = ucv_array_get(modules, idx);
-		mod = uc_vm_invoke(&vm, "require", 1, name);
-
-		if (mod)
-			register_variable(globals, ucv_string_get(name), mod);
-	}
-
-	rc = uc_vm_execute(&vm, entry, &res);
+	rc = uc_vm_execute(vm, entry, &res);
 
 	switch (rc) {
 	case STATUS_OK:
@@ -148,7 +111,6 @@ parse(uc_parse_config_t *config, uc_source_t *src,
 	}
 
 out:
-	uc_vm_free(&vm);
 	ucv_put(res);
 
 	return rc;
@@ -224,10 +186,11 @@ parse_envfile(FILE *fp)
 int
 main(int argc, char **argv)
 {
-	uc_value_t *env = NULL, *modules = NULL, *o, *p;
 	uc_source_t *source = NULL, *envfile = NULL;
-	int opt, rv = 0, trace = 0;
 	char *stdin = NULL, *c;
+	uc_vm_t vm = { 0 };
+	uc_value_t *o, *p;
+	int opt, rv = 0;
 
 	uc_parse_config_t config = {
 		.strict_declarations = false,
@@ -241,6 +204,20 @@ main(int argc, char **argv)
 		goto out;
 	}
 
+	uc_vm_init(&vm, &config);
+
+	/* load std functions into global scope */
+	uc_load_stdlib(uc_vm_scope_get(&vm));
+
+	/* register ARGV array */
+	o = ucv_array_new_length(&vm, argc);
+
+	for (opt = 0; opt < argc; opt++)
+		ucv_array_push(o, ucv_string_new(argv[opt]));
+
+	ucv_object_add(uc_vm_scope_get(&vm), "ARGV", o);
+
+	/* parse options */
 	while ((opt = getopt(argc, argv, "hlrtSRe:E:i:s:m:")) != -1)
 	{
 		switch (opt) {
@@ -337,32 +314,31 @@ main(int argc, char **argv)
 				goto out;
 			}
 
-			env = env ? env : ucv_object_new(NULL);
-
 			if (c > optarg && optarg[0]) {
-				p = ucv_object_new(NULL);
-				ucv_object_add(env, optarg, p);
+				p = ucv_object_new(&vm);
+				ucv_object_add(uc_vm_scope_get(&vm), optarg, p);
 			}
 			else {
-				p = env;
+				p = uc_vm_scope_get(&vm);
 			}
 
 			ucv_object_foreach(o, key, val)
-				ucv_object_add(p, key, ucv_get(val));
+				register_variable(p, key, ucv_get(val));
 
 			ucv_put(o);
 
 			break;
 
 		case 'm':
-			modules = modules ? modules : ucv_array_new(NULL);
+			o = uc_vm_invoke(&vm, "require", 1, ucv_string_new(optarg));
 
-			ucv_array_push(modules, ucv_string_new(optarg));
+			if (o)
+				register_variable(uc_vm_scope_get(&vm), optarg, o);
 
 			break;
 
 		case 't':
-			trace = 1;
+			uc_vm_trace_set(&vm, 1);
 			break;
 		}
 	}
@@ -383,13 +359,12 @@ main(int argc, char **argv)
 		goto out;
 	}
 
-	rv = parse(&config, source, env, modules, argc, argv, trace);
+	rv = compile(&vm, source);
 
 out:
-	ucv_put(modules);
-	ucv_put(env);
-
 	uc_source_put(source);
 
+	uc_vm_free(&vm);
+
 	return rv;
 }