Implement expression-based language redesign

This is the implementation of commit
ce68792c848caee2f184e7a6392d9f1e958da1a1.

4 files changed, 183 insertions, 155 deletions

diff --git a/include/cmd.h b/include/cmd.h
new file mode 100644
index 0000000..2cf69b4
--- /dev/null
+++ b/include/cmd.h
@@ -0,0 +1,66 @@
+#ifndef CERC_CMD_H
+#define CERC_CMD_H
+#include "type.h"
+
+struct ast_return {
+	struct ast_expr *value;
+};
+
+struct ast_break {
+	const char *label;
+	struct ast_expr *value;
+};
+
+struct ast_declaration {
+	bool mut;
+	const char *name;
+	struct ast_expr *value;
+};
+
+enum statement {
+	STM_RETURN,
+	STM_BREAK,
+	STM_CONTINUE,
+	STM_DECL,
+	STM_DEFER,
+};
+
+struct ast_statement {
+	enum statement action;
+	union {
+		struct ast_return ret;
+		struct ast_break brk;
+		struct ast_declaration decl;
+		struct assign_e *assign;
+		struct call_e *call;
+	} stmt;
+};
+
+struct ast_func {
+	bool exported;
+	const char *name;
+	struct type *ret;
+	struct ast_param *params;
+	int paramsz, paramlen;
+	struct ast_block *block;
+};
+struct ast_block {
+	const char *label;
+	struct ast_cmd *cmds;
+	int cmdsz, cmdlen;
+};
+
+enum command {
+	CMD_BLOCK,
+	CMD_STATEMENT,
+};
+
+struct ast_cmd {
+	enum command kind;
+	union {
+		struct ast_block blk;
+		struct ast_statement stmt;
+	} cmd;
+};
+
+#endif
diff --git a/include/expr.h b/include/expr.h
index 5a16f30..5f57349 100644
--- a/include/expr.h
+++ b/include/expr.h
@@ -1,6 +1,7 @@
 #ifndef CERC_EXPR_H
 #define CERC_EXPR_H
 #include <stdbool.h>
+#include "cmd.h"
 #include "lex.h"
 #include "type.h"
 
@@ -15,6 +16,38 @@ struct array_e {
 	int elemsz, elemlen;
 };
 
+struct elseif {
+	struct disjunction_e *cond;
+	struct ast_block blk;
+};
+
+struct if_e {
+	struct disjunction_e *cond;
+	struct ast_block blk;
+	struct elseif *alts;
+	struct ast_block *alt;
+	int altsz, altlen;
+};
+
+struct for_e {
+	struct ast_assign *init, *action;
+	struct disjunction_e *cond;
+	struct ast_block blk;
+};
+
+enum control {
+	CTL_IF,
+	CTL_FOR,
+};
+
+struct control_e {
+	enum control kind;
+	union {
+		struct if_e branch;
+		struct for_e loop;
+	} ctl;
+};
+
 enum literal {
 	LIT_BOOL,
 	LIT_STRING,
@@ -32,26 +65,52 @@ struct literal_e {
 	} lit;
 };
 
-struct call_e {
+struct location_e {
 	struct path *path;
+	struct loc_postfix *subs;
+	int subsz, sublen;
+};
+
+struct assign_e {
+	struct location_e dst;
+	struct ast_expr *value;
+};
+
+struct call_e {
+	struct location_e *loc;
 	struct disjunction_e *args;
 	int argsz, arglen;
 };
 
+enum named {
+	NMD_ASSIGN,
+	NMD_CALL,
+	NMD_LOCATION,
+};
+
+struct named_e {
+	enum named kind;
+	struct location_e loc;
+	union {
+		struct assign_e assign;
+		struct call_e call;
+	} nmd;
+};
+
 enum primary {
+	PRM_CONTROL,
 	PRM_GROUPING,
 	PRM_LITERAL,
-	PRM_CALL,
-	PRM_PATH,
+	PRM_NAMED,
 };
 
 struct primary_e {
 	enum primary kind;
 	union {
+		struct control_e ctl;
 		struct disjunction_e *grp;
 		struct literal_e lit;
-		struct call_e call;
-		struct path *path;
+		struct named_e nmd;
 	} prim;
 };
 
diff --git a/include/parse.h b/include/parse.h
index 0889f91..5b97353 100644
--- a/include/parse.h
+++ b/include/parse.h
@@ -18,27 +18,6 @@ struct ast_param {
 	struct type type;
 };
 
-struct ast_block {
-	const char *label;
-	struct ast_cmd *cmds;
-	int cmdsz, cmdlen;
-};
-
-struct ast_return {
-	struct ast_expr *value;
-};
-
-struct ast_break {
-	const char *label;
-	struct ast_expr *value;
-};
-
-struct ast_declaration {
-	bool mut;
-	const char *name;
-	struct ast_expr value;
-};
-
 enum subfield {
 	SUB_INDEX,
 	SUB_FIELD,
@@ -52,94 +31,6 @@ struct loc_postfix {
 	} id;
 };
 
-struct ast_location {
-	const char *name;
-	struct loc_postfix *subs;
-	int subsz, sublen;
-};
-
-struct ast_assign {
-	struct ast_location dst;
-	struct ast_expr value;
-};
-
-enum statement {
-	STM_RETURN,
-	STM_BREAK,
-	STM_CONTINUE,
-	STM_DECL,
-	STM_ASSIGN,
-	STM_CALL,
-	STM_DEFER,
-};
-
-struct ast_statement {
-	enum statement action;
-	union {
-		struct ast_return ret;
-		struct ast_break brk;
-		struct ast_declaration decl;
-		struct ast_assign assign;
-		struct call_e call;
-	} stmt;
-};
-
-struct ast_elseif {
-	struct ast_expr cond;
-	struct ast_block blk;
-};
-
-struct ast_if {
-	struct ast_expr cond;
-	struct ast_block blk;
-	struct ast_elseif *alts;
-	struct ast_block *alt;
-	int altsz, altlen;
-};
-
-struct ast_for {
-	struct ast_assign *init, *action;
-	struct ast_expr cond;
-	struct ast_block blk;
-};
-
-enum control {
-	CTL_IF,
-	CTL_FOR,
-};
-
-struct ast_control {
-	enum control kind;
-	union {
-		struct ast_if branch;
-		struct ast_for loop;
-	} ctl;
-};
-
-enum command {
-	CMD_BLOCK,
-	CMD_STATEMENT,
-	CMD_CONTROL,
-};
-
-struct ast_cmd {
-	enum command kind;
-	union {
-		struct ast_block blk;
-		struct ast_statement stmt;
-		struct ast_control ctl;
-	} cmd;
-};
-
-struct ast_func {
-	bool exported;
-	const char *name;
-	struct type ret;
-	struct ast_param *params;
-	int paramsz, paramlen;
-	struct ast_block block;
-};
-
 enum const_global {
 	CST_TYPE,
 	CST_BOOL,
diff --git a/src/parse.c b/src/parse.c
index ee115d8..c5ced09 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -12,6 +12,9 @@ static bool parse_disjunction_e(struct lexer *lexer,
 static bool parse_array(struct lexer *lexer, struct type *out);
 static bool parse_type(struct lexer *lexer, struct type *out);
 static bool parse_block(struct lexer *lexer, struct ast_block *out);
+static bool parse_control_e(struct lexer *lexer, struct control_e *out);
+static bool parse_location(struct lexer *lexer, struct location_e *out);
+static bool parse_assignment_e(struct lexer *lexer, struct assign_e *out);
 
 static noreturn void
 error(struct location loc, const char *fmt, ...)
@@ -188,14 +191,13 @@ parse_literal_e(struct lexer *lexer, struct literal_e *out)
 
 // Invariant: Only called from parse_primary_e with path already consumed.
 static bool
-parse_call_e(struct lexer *lexer, struct call_e *out, struct path path)
+parse_call_e(struct lexer *lexer, struct call_e *out, struct location_e *loc)
 {
 	if (!match(lexer, T_LPAREN)) {
 		return false;
 	}
 
-	out->path = must_malloc(sizeof(struct path));
-	*out->path = path;
+	out->loc = loc;
 
 	out->args = must_calloc(1, sizeof(struct disjunction_e));
 	out->argsz = 1;
@@ -219,8 +221,32 @@ parse_call_e(struct lexer *lexer, struct call_e *out, struct path path)
 }
 
 static bool
+parse_named_e(struct lexer *lexer, struct named_e *out)
+{
+	if (!parse_location(lexer, &out->loc)) {
+		return false;
+	}
+
+	if (parse_assignment_e(lexer, &out->nmd.assign)) {
+		out->kind = NMD_ASSIGN;
+		return true;
+	}
+	if (parse_call_e(lexer, &out->nmd.call, &out->loc)) {
+		out->kind = NMD_CALL;
+		return true;
+	}
+
+	out->kind = NMD_LOCATION;
+	return true;
+}
+
+static bool
 parse_primary_e(struct lexer *lexer, struct primary_e *out)
 {
+	if (parse_control_e(lexer, &out->prim.ctl)) {
+		out->kind = PRM_CONTROL;
+		return true;
+	}
 	out->prim.grp = must_malloc(sizeof(struct disjunction_e));
 	if (parse_grouping_e(lexer, out->prim.grp)) {
 		out->kind = PRM_GROUPING;
@@ -231,14 +257,12 @@ parse_primary_e(struct lexer *lexer, struct primary_e *out)
 		out->kind = PRM_LITERAL;
 		return true;
 	}
-	out->prim.path = must_malloc(sizeof(struct path));
-	if (parse_path(lexer, out->prim.path)) {
-		out->kind = PRM_PATH;
-		if (parse_call_e(lexer, &out->prim.call, *out->prim.path)) {
-			out->kind = PRM_CALL;
-		}
+	if (parse_named_e(lexer, &out->prim.nmd)) {
+		out->kind = PRM_NAMED;
 		return true;
 	}
+
+	return false;
 }
 
 static bool
@@ -1178,7 +1202,8 @@ parse_declaration(struct lexer *lexer, struct ast_declaration *out)
 		error(lex_loc(lexer), "syntax error: expected '='");
 	}
 
-	if (!parse_expr(lexer, &out->value)) {
+	out->value = must_malloc(sizeof(struct ast_expr));
+	if (!parse_expr(lexer, out->value)) {
 		error(lex_loc(lexer), "syntax error: expected expression");
 	}
 
@@ -1235,11 +1260,11 @@ parse_loc_postfix(struct lexer *lexer, struct loc_postfix *out)
 }
 
 static bool
-parse_location(struct lexer *lexer, struct ast_location *out)
+parse_location(struct lexer *lexer, struct location_e *out)
 {
-	struct token name;
-	if (lex(lexer, &name) != T_NAME) {
-		unlex(lexer, &name);
+	out->path = must_malloc(sizeof(struct path));
+	if (!parse_path(lexer, out->path)) {
+		free(out->path);
 		return false;
 	}
 
@@ -1261,7 +1286,7 @@ parse_location(struct lexer *lexer, struct ast_location *out)
 }
 
 static bool
-parse_assignment(struct lexer *lexer, struct ast_assign *out)
+parse_assignment_e(struct lexer *lexer, struct assign_e *out)
 {
 	if (!parse_location(lexer, &out->dst)) {
 		return false;
@@ -1271,7 +1296,8 @@ parse_assignment(struct lexer *lexer, struct ast_assign *out)
 		error(lex_loc(lexer), "syntax error: expected '='");
 	}
 
-	if (!parse_expr(lexer, &out->value)) {
+	out->value = must_malloc(sizeof(struct ast_expr));
+	if (!parse_expr(lexer, out->value)) {
 		error(lex_loc(lexer), "syntax error: expected expression");
 	}
 
@@ -1292,12 +1318,12 @@ parse_defer(struct lexer *lexer, struct call_e *out)
 		return false;
 	}
 
-	struct path path;
-	if (!parse_path(lexer, &path)) {
+	struct location_e *loc = must_malloc(sizeof(struct location_e));
+	if (!parse_location(lexer, loc)) {
 		error(lex_loc(lexer), "syntax error: expected path");
 	}
 
-	if (!parse_call_e(lexer, out, path)) {
+	if (!parse_call_e(lexer, out, loc)) {
 		error(lex_loc(lexer), "syntax error: expected call");
 	}
 
@@ -1335,33 +1361,21 @@ parse_statement(struct lexer *lexer, struct ast_statement *out)
 		}
 		return true;
 	}
-	if (parse_assignment(lexer, &out->stmt.assign)) {
-		out->action = STM_ASSIGN;
-		if (!match(lexer, T_SEMICOLON)) {
-			error(lex_loc(lexer), "syntax error: expected semicolon");
-		}
-		return true;
-	}
-	if (parse_call(lexer, &out->stmt.call)) {
-		out->action = STM_CALL;
-		if (!match(lexer, T_SEMICOLON)) {
-			error(lex_loc(lexer), "syntax error: expected semicolon");
-		}
-		return true;
-	}
-	if (parse_defer(lexer, &out->stmt.call)) {
+	out->stmt.call = must_malloc(sizeof(struct call_e));
+	if (parse_defer(lexer, out->stmt.call)) {
 		out->action = STM_DEFER;
 		if (!match(lexer, T_SEMICOLON)) {
 			error(lex_loc(lexer), "syntax error: expected semicolon");
 		}
 		return true;
 	}
+	free(out->stmt.call);
 
 	return false;
 }
 
 static bool
-parse_control(struct lexer *lexer, struct ast_control *out)
+parse_control_e(struct lexer *lexer, struct control_e *out)
 {
 	/* TODO */
 	return false;
@@ -1378,10 +1392,6 @@ parse_command(struct lexer *lexer, struct ast_cmd *out)
 		out->kind = CMD_STATEMENT;
 		return true;
 	}
-	if (parse_control(lexer, &out->cmd.ctl)) {
-		out->kind = CMD_CONTROL;
-		return true;
-	}
 
 	return false;
 }
@@ -1476,9 +1486,11 @@ parse_function(struct lexer *lexer, struct ast_func *out)
 		error(lex_loc(lexer), "syntax error: expected ')'");
 	}
 
-	bool nonvoid = parse_type(lexer, &out->ret);
+	out->ret = must_malloc(sizeof(struct type));
+	bool nonvoid = parse_type(lexer, out->ret);
 
-	if (!parse_block(lexer, &out->block)) {
+	out->block = must_malloc(sizeof(struct ast_block));
+	if (!parse_block(lexer, out->block)) {
 		error(lex_loc(lexer), "syntax error: expected block");
 	}