Things.

Makefile

@@ -44,13 +44,14 @@ grammars: $(SRC_DIR)/grammar.y
 	@ echo -e "$(WHITE_BOLD)Generating grammars...$(RESETCOLOR) bison $< -o$(GRAM_DIR)/grammar.tab.c -H$(GRAM_DIR)/grammar.tab.h"
 	@ bison $< -o$(GRAM_DIR)/grammar.tab.c -H$(GRAM_DIR)/grammar.tab.h
 
-# Link to final binary.
+
-$(TARGET): $(OBJ_FILES)
+# Compile grammars.
-	@ echo -e "$(WHITE_BOLD)Linking $(WHITE)$(TARGET)$(WHITE_BOLD)...$(RESETCOLOR) $(CC) -o $(TARGET) $(OBJ_FILES) $(LDFLAGS)"
+$(OBJ_DIR)/grammar.o: $(GRAM_DIR)/grammar.tab.c $(GRAM_DIR)/grammar.tab.h $(OBJ_DIR)/lexer.o
-	@ $(LINK) -o $(TARGET) $(OBJ_FILES) $(LDFLAGS)
+	$(CC) $(CFLAGS) -c $< -o $@
 
 # Lexer depends on grammars.
-$(OBJ_DIR)/lexer.o: grammars
+$(OBJ_DIR)/lexer.o: $(SRC_DIR)/lexer.c
+	$(CC) $(CFLAGS) -c $< -o $@
 
 # Compile project sources.
 $(OBJ_DIR)/%.o: $(SRC_DIR)/%.c $(INC_DIR)/%.h
@@ -58,6 +59,11 @@ $(OBJ_DIR)/%.o: $(SRC_DIR)/%.c $(INC_DIR)/%.h
 	@ echo -e "$(WHITE_BOLD)Compiling $(WHITE)$<$(WHITE_BOLD)... $(RESETCOLOR)$(CC) $(CFLAGS) -c $< -o $@"
 	@ $(CC) $(CFLAGS) -c $< -o $@
 
+# Link to final binary.
+$(TARGET): $(OBJ_FILES) $(OBJ_DIR)/grammar.o
+	@ echo -e "$(WHITE_BOLD)Linking $(WHITE)$(TARGET)$(WHITE_BOLD)...$(RESETCOLOR) $(CC) -o $(TARGET) $(OBJ_FILES) $(LDFLAGS)"
+	@ $(LINK) -o $(TARGET) $(OBJ_FILES) $(OBJ_DIR)/grammar.o $(LDFLAGS)
+
 # Compile test sources.
 $(TEST_OBJ_DIR)/%.o: $(TEST_DIR)/%.c
 	@ mkdir -p $(TEST_OBJ_DIR)
@@ -76,4 +82,3 @@ clean:
 	@ rm -rf $(OBJ_DIR)/*.o $(TEST_OBJ_DIR)/*.o $(TEST_BUILD_DIR)/test.out $(TARGET)
 
 .PHONY: all clean test nocolor release run
-

src/ast.c

@@ -10,7 +10,7 @@ static char* asttype_names[] = {
 };
 #endif
 
-ASTTypeNum* ast_type_num_init(int val) {
+ASTTypeNum* ast_type_num_init(AST* val) {
     talloc(ASTTypeNum, num);
 
     num->val = val;
@@ -19,7 +19,8 @@ ASTTypeNum* ast_type_num_init(int val) {
 }
 
 void ast_type_num_destroy(ASTTypeNum* num) {
-    if (!num) return
+    if (!num)
+        return
 
             free(num);
 }
@@ -35,7 +36,8 @@ ASTTypeCall* ast_type_call_init(char* to, size_t argc, AST** argv) {
 }
 
 void ast_type_call_destroy(ASTTypeCall* call) {
-    if (!call) return
+    if (!call)
+        return
 
             free(call->to);
     for (size_t i = 0; i < call->argc; i++) free(call->argv[i]);

src/grammar.y

@@ -1,11 +1,14 @@
+%{
+#include "../../src/include/ast.h"
+#include "../../src/include/lexer.h"
+int yylex (void);
+void yyerror (char const *);
+%}
+
 %code requires {
     #include "../../src/include/ast.h"
 }
 
-%{
-#include "../../src/include/ast.h"
-%}
-
 %union {
     int intval;
     char* strval;
@@ -20,8 +23,8 @@
 %%
 
 exp:
-   NUM {}
+   NUM { $$ = ast_type_num_init($1); }
-   | exp PLUS exp { $$ = ast_type_call_init("+", 2, [ast_type_num_init($1), ast_type_num_init(int val)]}
+   | NUM PLUS NUM { AST* argv[2] = {ast_type_num_init($1), ast_type_num_init($1)}; $$ = ast_type_call_init("+", 2, argv);}
    ;
 
 %%

src/include/ast.h

@@ -18,10 +18,10 @@ AST* ast_init(ASTType type, void* data);
 void ast_destroy(AST* ast);
 
 typedef struct {
-    int val;
+    AST* val;
 } ASTTypeNum;
 
-ASTTypeNum* ast_type_num_init(int val);
+ASTTypeNum* ast_type_num_init(AST* val);
 void ast_type_num_destroy(ASTTypeNum* num);
 
 typedef struct {

src/include/lexer.h

@@ -72,5 +72,6 @@ void lexerstate_print_raw();
 void lexer_set_global(const char* str);
 
 int yylex();
+void yyerror(char const* s);
 
 #endif

src/lexer.c

@@ -172,3 +172,4 @@ int yylex() {
 
     return 0;
 }
+void yyerror(char const* s) { fprintf(stderr, "%s\n", s); }