Begin semantics

src/deelang.c

@@ -1,3 +1,4 @@
+#include "syntax.h"
 #include "lexer.h"
 #include "parser.h"
 

src/lexer.l

@@ -1,4 +1,5 @@
 %{
+#include "syntax.h"
 #include "parser.h"
 int stack[100]; // Max indentation depth
 int sp = -1;

src/parser.y

@@ -8,14 +8,19 @@ int yyerror(const char* p) { fprintf(stderr, p); }
 %define parse.trace
 
 %union {
-       char* sym;
+       expr_t expr;
-       float num;
+       binop_t binop;
+       atom_t id;
+       num_t num;
+       char *sym;
+       string_t string;
 }
 
-%token <sym> ID
+%token <id> ID
-%token STOP
 %token <num> NUM
-%token STRING
+%token <string> STRING
+
+%token STOP
 %token INDENT DEDENT
 %token IF ELIF ELSE
 
@@ -25,6 +30,8 @@ int yyerror(const char* p) { fprintf(stderr, p); }
 %left '/' '*'
 %left MAPS
 
+%nterm <expr> expr
+
 %%
 program:	statements | statements statement;
 statements:	statements statement STOP
@@ -41,8 +48,10 @@ expr:		funcdef
 		| expr '-' expr
 		| expr '*' expr
 		| expr '/' expr
-		| '(' expr ')'
+		| '(' expr ')' {$$ = $2;}
-		| ID | NUM | STRING;
+		| ID {$$.id = $1; $$.type = ID;}
+		| NUM {$$.num = $1; $$.type = NUM;}
+		| STRING {$$.string = $1; $$.type = STRING;};
 		
 funcdef: 	param MAPS expr | param MAPS block;
 param:	 	ID | '_' | // null production;

src/syntax.h

@@ -1,6 +1,26 @@
 #ifndef SYNTAX_H
 #define SYNTAX_H
 
+typedef float num_t;
+typedef char* atom_t;
+typedef char* string_t;
+typedef struct expr_t expr_t;
+typedef struct binop_t binop_t;
 
+struct expr_t {
+  int type;
+  union {
+    atom_t id;
+    num_t num;
+    string_t string;
+    binop_t *binop;
+  };
+};
+
+struct binop_t {
+  expr_t *first;
+  expr_t *second;
+  int op;
+};
 
 #endif /* SYNTAX_H */