diff --git a/src/ast.c b/src/ast.c
index fd6019c..795e946 100644
--- a/src/ast.c
+++ b/src/ast.c
@@ -10,6 +10,7 @@ static char* asttype_names[] = {
     [AST_TYPE_CALL] = "FUNC CALL",
     [AST_TYPE_NUM] = "NUMBER",
     [AST_TYPE_VREF] = "VAR REFERENCE",
+    [AST_TYPE_VDEF] = "VAR DEFINITION",
     [AST_TYPE_BLOCK] = "BLOCK",
 };
 
@@ -29,6 +30,7 @@ void ast_destroy(AST* ast) {
         case AST_TYPE_NUM:  ast_num_data_destroy(ast->data); break;
         case AST_TYPE_CALL: ast_call_data_destroy(ast->data); break;
         case AST_TYPE_VREF: ast_vref_data_destroy(ast->data); break;
+        case AST_TYPE_VDEF: ast_vdef_data_destroy(ast->data); break;
         default:
             log_dbgf("Unknown ast type %d (max: %d)", ast->type, AST_TYPE_MAX);
     }
@@ -50,6 +52,7 @@ void ast_print_i(AST* ast, int i) {
             break;
         case AST_TYPE_CALL: ast_call_print(ast->data, i + 2); break;
         case AST_TYPE_VREF: ast_vref_print(ast->data, i + 2); break;
+        case AST_TYPE_VDEF: ast_vdef_print(ast->data, i + 2); break;
         default:            exit(1);
     }
     INDENT_FIELD_NONL_END;
@@ -105,6 +108,33 @@ void ast_call_print(ASTCallData* data, int i) {
     INDENT_END;
 }
 
+ASTVDefData* ast_vdef_data_init(char* name, AST* val) {
+    talloc(ASTVDefData, vdef);
+
+    vdef->name = name;
+    vdef->val = val;
+
+    return vdef;
+}
+
+void ast_vdef_data_destroy(ASTVDefData* vdef) {
+    ast_destroy(vdef->val);
+    free(vdef->name);
+    free(vdef);
+}
+
+void ast_vdef_print(ASTVDefData* vdef, int depth) {
+    INDENT_BEGIN(depth);
+
+    INDENT_TITLE("ASTVDefData", vdef);
+    INDENT_FIELD("name", "%s", vdef->name);
+    INDENT_FIELD_EXT_NONL_START("val");
+    ast_print_i(vdef->val, depth + 2);  // 2 because already indented.
+    INDENT_FIELD_NONL_END;
+
+    INDENT_END;
+}
+
 ASTVrefData* ast_vref_data_init(char* to) {
     talloc(ASTVrefData, vref);
 
diff --git a/src/exec.c b/src/exec.c
index a34f74b..f4f5b97 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -14,6 +14,7 @@ ASTNumData exec_exp(AST* ast) {
         case AST_TYPE_CALL: return exec_call(ast);
         case AST_TYPE_NUM:  return *(ASTNumData*)ast->data;
         case AST_TYPE_VREF: return exec_vref(ast);
+        case AST_TYPE_VDEF: return exec_vdef(ast);
         default:            printf("what\n");
                             exit(1);
     }
@@ -68,6 +69,12 @@ ASTNumData exec_call(AST* ast) {
     return -1000;
 }
 
+ASTNumData exec_vdef(AST* ast) {
+    ASTVDefData* data = (ASTVDefData*) ast->data;
+    AST* val = data->val;
+    return exec_exp(val);
+}
+
 ASTNumData exec_vref(AST* ast) {
     return *ast_num_data_init(42.42);
 }
diff --git a/src/grammar.y b/src/grammar.y
index 946ec05..839a707 100644
--- a/src/grammar.y
+++ b/src/grammar.y
@@ -33,6 +33,8 @@
 %token GROUPE // Group end ).
 %token SEP // Seperator ,.
 
+%token EQ // Equals =.
+
 %token EXPSEP // Expression seperator ;.
 
 %token<strval> WORD // Word, i.e. keyword.
@@ -116,11 +118,16 @@ exp:
 
     | GROUPS exp GROUPE { $$ = $2; }
 
-    // Variable reference.
-    | WORD {
-        $$ = ast_init(AST_TYPE_VREF, ast_vref_data_init($1));
+    // Variable definition.
+    | WORD EQ exp {
+        $$ = ast_init(AST_TYPE_VDEF, ast_vdef_data_init($1, $3));
     }
 
+    // Variable reference.
+    //| WORD {
+    //    $$ = ast_init(AST_TYPE_VREF, ast_vref_data_init($1));
+    //}
+
     | WORD GROUPS arg GROUPE {
         size_t argc = $3->ln;
         AST** argv = $3->buf;
diff --git a/src/include/ast.h b/src/include/ast.h
index cf38ebc..a5bc766 100644
--- a/src/include/ast.h
+++ b/src/include/ast.h
@@ -6,6 +6,7 @@
 typedef enum {
     AST_TYPE_NUM,   // A number.
     AST_TYPE_CALL,  // A function call.
+    AST_TYPE_VDEF,  // A variable definition.
     AST_TYPE_VREF,  // A variable reference.
     AST_TYPE_BLOCK, // A block of code (scope).
     AST_TYPE_MAX = AST_TYPE_BLOCK,
@@ -37,6 +38,18 @@ ASTCallData* ast_call_data_init(char* to, size_t argc, AST** argv);
 void ast_call_data_destroy(ASTCallData* call);
 void ast_call_print(ASTCallData*, int i);
 
+// A variable definition's data.
+typedef struct {
+    char* name;
+    AST* val;
+} ASTVDefData;
+
+ASTVDefData* ast_vdef_data_init(char* name, AST* val);
+// Destroys the vdef, its name, and its ->val.
+void ast_vdef_data_destroy(ASTVDefData* vdef);
+void ast_vdef_print(ASTVDefData*, int depth);
+
+// A variable reference's data.
 typedef struct {
     char* to; // What the reference's to.
 } ASTVrefData;
diff --git a/src/include/exec.h b/src/include/exec.h
index cbf1353..4caaeca 100644
--- a/src/include/exec.h
+++ b/src/include/exec.h
@@ -6,6 +6,7 @@
 ASTNumData exec_exp(AST* ast);
 ASTNumData exec_call(AST* ast);
 ASTNumData exec_vref(AST* ast);
+ASTNumData exec_vdef(AST* ast);
 void exec_print(double n);
 
 #endif
diff --git a/src/lexer.c b/src/lexer.c
index b3bcee9..53dd80f 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -115,6 +115,7 @@ int yylex() {
         case ';': return EXPSEP;
         case '{': return BLOCKS;
         case '}': return BLOCKE;
+        case '=': return EQ;
         default:   fprintf(stderr, "Unexpected character: %c\n", c);
     }