add: parse proc declarations

5 files changed, 170 insertions, 2 deletions

diff --git a/src/lexer/lexer.c b/src/lexer/lexer.c
index ca51bb8..6018fab 100644
--- a/src/lexer/lexer.c
+++ b/src/lexer/lexer.c
@@ -22,8 +22,8 @@ static enum TokenType identifier_type(const char* start, size_t length)
 		const char* text;
 		size_t length;
 		enum TokenType type;
-	}
-	keywords[] = {
+	} keywords[] = 
+	{
 		{ "const",   5, TOKEN_CONST   },
 		{ "data",    4, TOKEN_DATA    },
 		{ "proc",    4, TOKEN_PROC    },
diff --git a/src/main.c b/src/main.c
index b351bd8..e65362c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -46,6 +46,20 @@ int main(int argc, char** argv)
 			(int)decl.value.length, decl.value.start);
 	}
 
+	for (size_t i = 0; i < program.proc_count; i += 1)
+	{
+		struct ProcDecl proc = program.procs[i];
+		printf("proc %.*s(", (int)proc.name.length, proc.name.start);
+		for (size_t p = 0; p < proc.param_count; p += 1)
+		{
+			struct Param param = proc.params[p];
+			printf("%s%.*s: %.*s", p == 0 ? "" : ", ",
+				(int)param.name.length, param.name.start,
+				(int)param.reg.length, param.reg.start);
+		}
+		printf(")\n");
+	}
+
 	free_program(&program);
 	free_file(&source);
 }
diff --git a/src/parser/ast.c b/src/parser/ast.c
index 3f360cc..b002ff2 100644
--- a/src/parser/ast.c
+++ b/src/parser/ast.c
@@ -11,6 +11,9 @@ struct Program create_program(void)
 	program.data_decls = NULL;
 	program.data_count = 0;
 	program.data_capacity = 0;
+	program.procs = NULL;
+	program.proc_count = 0;
+	program.proc_capacity = 0;
 	return program;
 }
 
@@ -18,12 +21,20 @@ void free_program(struct Program* program)
 {
 	free(program->consts);
 	free(program->data_decls);
+
+	for (size_t i = 0; i < program->proc_count; i += 1)
+		free(program->procs[i].params);
+	free(program->procs);
+
 	program->consts = NULL;
 	program->const_count = 0;
 	program->const_capacity = 0;
 	program->data_decls = NULL;
 	program->data_count = 0;
 	program->data_capacity = 0;
+	program->procs = NULL;
+	program->proc_count = 0;
+	program->proc_capacity = 0;
 }
 
 // TODO: generalize this growable-array boilerplate once a third list appears
@@ -52,3 +63,38 @@ void add_data(struct Program* program, struct DataDecl decl)
 	program->data_decls[program->data_count] = decl;
 	program->data_count += 1;
 }
+
+struct ProcDecl create_proc(void)
+{
+	struct ProcDecl proc;
+	proc.params = NULL;
+	proc.param_count = 0;
+	proc.param_capacity = 0;
+	return proc;
+}
+
+void add_param(struct ProcDecl* proc, struct Param param)
+{
+	if (proc->param_count == proc->param_capacity)
+	{
+		size_t capacity = proc->param_capacity < 4 ? 4 : proc->param_capacity * 2;
+		proc->params = realloc(proc->params, capacity * sizeof(struct Param));
+		proc->param_capacity = capacity;
+	}
+
+	proc->params[proc->param_count] = param;
+	proc->param_count += 1;
+}
+
+void add_proc(struct Program* program, struct ProcDecl decl)
+{
+	if (program->proc_count == program->proc_capacity)
+	{
+		size_t capacity = program->proc_capacity < 8 ? 8 : program->proc_capacity * 2;
+		program->procs = realloc(program->procs, capacity * sizeof(struct ProcDecl));
+		program->proc_capacity = capacity;
+	}
+
+	program->procs[program->proc_count] = decl;
+	program->proc_count += 1;
+}
diff --git a/src/parser/ast.h b/src/parser/ast.h
index 30dd1e7..665bfd2 100644
--- a/src/parser/ast.h
+++ b/src/parser/ast.h
@@ -16,6 +16,20 @@ struct DataDecl
 	struct Token value;
 };
 
+struct Param
+{
+	struct Token name;
+	struct Token reg;
+};
+
+struct ProcDecl
+{
+	struct Token name;
+	struct Param* params;
+	size_t param_count;
+	size_t param_capacity;
+};
+
 struct Program
 {
 	struct ConstDecl* consts;
@@ -25,9 +39,17 @@ struct Program
 	struct DataDecl* data_decls;
 	size_t data_count;
 	size_t data_capacity;
+
+	struct ProcDecl* procs;
+	size_t proc_count;
+	size_t proc_capacity;
 };
 
 struct Program create_program(void);
 void free_program(struct Program* program);
 void add_const(struct Program* program, struct ConstDecl decl);
 void add_data(struct Program* program, struct DataDecl decl);
+
+struct ProcDecl create_proc(void);
+void add_param(struct ProcDecl* proc, struct Param param);
+void add_proc(struct Program* program, struct ProcDecl decl);
diff --git a/src/parser/parser.c b/src/parser/parser.c
index 4fb85ef..acd4b7a 100644
--- a/src/parser/parser.c
+++ b/src/parser/parser.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "parser/parser.h"
 
@@ -27,6 +28,15 @@ static void error_at(struct Parser* parser, struct Token token, const char* mess
 	parser->had_error = true;
 }
 
+static bool match_token(struct Parser* parser, enum TokenType type)
+{
+	if (!check(parser, type))
+		return false;
+
+	advance_parser(parser);
+	return true;
+}
+
 static bool consume(struct Parser* parser, enum TokenType type, const char* message)
 {
 	if (check(parser, type))
@@ -77,6 +87,76 @@ static bool parse_data(struct Parser* parser, struct Program* program)
 	return true;
 }
 
+static bool parse_params(struct Parser* parser, struct ProcDecl* proc)
+{
+	if (check(parser, TOKEN_RIGHT_PAREN))
+		return true;
+
+	do
+	{
+		struct Param param;
+
+		if (!consume(parser, TOKEN_IDENTIFIER, "expected parameter name"))
+			return false;
+		param.name = parser->previous;
+
+		if (!consume(parser, TOKEN_COLON, "expected ':' after parameter name"))
+			return false;
+
+		if (!consume(parser, TOKEN_IDENTIFIER, "expected register after ':'"))
+			return false;
+		param.reg = parser->previous;
+
+		add_param(proc, param);
+	}
+	while (match_token(parser, TOKEN_COMMA));
+
+	return true;
+}
+
+static bool parse_proc(struct Parser* parser, struct Program* program)
+{
+	struct ProcDecl decl = create_proc();
+
+	if (!consume(parser, TOKEN_IDENTIFIER, "expected procedure name after 'proc'"))
+		goto error;
+	decl.name = parser->previous;
+
+	if (match_token(parser, TOKEN_LEFT_PAREN))
+	{
+		if (!parse_params(parser, &decl))
+			goto error;
+		if (!consume(parser, TOKEN_RIGHT_PAREN, "expected ')' after parameters"))
+			goto error;
+	}
+
+	if (!consume(parser, TOKEN_LEFT_BRACE, "expected '{' to begin procedure body"))
+		goto error;
+
+	// TODO: parse body statements; for now skip the braced block
+	int depth = 1;
+	while (depth > 0)
+	{
+		if (check(parser, TOKEN_EOF))
+		{
+			error_at(parser, parser->current, "unterminated procedure body");
+			goto error;
+		}
+		if (check(parser, TOKEN_LEFT_BRACE))
+			depth += 1;
+		else if (check(parser, TOKEN_RIGHT_BRACE))
+			depth -= 1;
+		advance_parser(parser);
+	}
+
+	add_proc(program, decl);
+	return true;
+
+error:
+	free(decl.params);
+	return false;
+}
+
 bool parse_program(struct Lexer* lexer, struct Program* out)
 {
 	struct Parser parser;
@@ -100,6 +180,12 @@ bool parse_program(struct Lexer* lexer, struct Program* out)
 			if (!parse_data(&parser, out))
 				return false;
 		}
+		else if (check(&parser, TOKEN_PROC))
+		{
+			advance_parser(&parser);
+			if (!parse_proc(&parser, out))
+				return false;
+		}
 		else
 		{
 			error_at(&parser, parser.current, "expected a top-level declaration");