From 8b01407374f63ae1bd7d1467b633e2b9c5bab2b3 Mon Sep 17 00:00:00 2001
From: Jacob Signorovitch <jacob.signorovitch@gmail.com>
Date: Mon, 20 Jan 2025 14:47:58 -0500
Subject: [PATCH 1/2] Added initial support for variables.

They are now parsed correctly, though they cannot be defined manually
and all have a value of 42.42.
---
 src/ast.c          | 14 ++++++++++++--
 src/exec.c         |  5 +++++
 src/grammar.y      |  4 +++-
 src/include/exec.h |  1 +
 4 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/ast.c b/src/ast.c
index 3fa9e4d..c923630 100644
--- a/src/ast.c
+++ b/src/ast.c
@@ -27,6 +27,7 @@ void ast_destroy(AST* ast) {
     switch (ast->type) {
         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;
         default:
             log_dbgf("Unknown ast type %d (max: %d)", ast->type, AST_TYPE_MAX);
     }
@@ -103,9 +104,18 @@ void ast_call_print(ASTCallData* data, int i) {
     INDENT_END;
 }
 
-ASTVrefData* ast_vref_data_init(char* to) {}
+ASTVrefData* ast_vref_data_init(char* to) {
+    talloc(ASTVrefData, vref);
 
-void ast_vref_data_destroy(ASTVrefData* vref) {}
+    vref->to = to;
+
+    return vref;
+}
+
+void ast_vref_data_destroy(ASTVrefData* vref) {
+    free(vref->to);
+    free(vref);
+}
 
 void ast_vref_print(ASTVrefData* data, int i) {
     INDENT_BEGIN(i);
diff --git a/src/exec.c b/src/exec.c
index d20d32a..a34f74b 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -13,6 +13,7 @@ ASTNumData exec_exp(AST* ast) {
     switch (ast->type) {
         case AST_TYPE_CALL: return exec_call(ast);
         case AST_TYPE_NUM:  return *(ASTNumData*)ast->data;
+        case AST_TYPE_VREF: return exec_vref(ast);
         default:            printf("what\n");
                             exit(1);
     }
@@ -67,4 +68,8 @@ ASTNumData exec_call(AST* ast) {
     return -1000;
 }
 
+ASTNumData exec_vref(AST* ast) {
+    return *ast_num_data_init(42.42);
+}
+
 void exec_print(double n) { printf("= %lf\n", n); }
diff --git a/src/grammar.y b/src/grammar.y
index 8d19bcc..df7ddcc 100644
--- a/src/grammar.y
+++ b/src/grammar.y
@@ -84,7 +84,9 @@ exp:
     | LGROUP exp RGROUP { $$ = $2; }
 
     // Variable reference.
-    //| WORD
+    | WORD {
+        $$ = ast_init(AST_TYPE_VREF, ast_vref_data_init($1));
+    }
 
     | WORD LGROUP arg RGROUP {
         size_t argc = $3->ln;
diff --git a/src/include/exec.h b/src/include/exec.h
index 53ee7df..cbf1353 100644
--- a/src/include/exec.h
+++ b/src/include/exec.h
@@ -5,6 +5,7 @@
 
 ASTNumData exec_exp(AST* ast);
 ASTNumData exec_call(AST* ast);
+ASTNumData exec_vref(AST* ast);
 void exec_print(double n);
 
 #endif

From 27e61471a89ca98021d9e0b6c9d92afacfd0025b Mon Sep 17 00:00:00 2001
From: Jacob <jacob.signorovitch@gmail.com>
Date: Sat, 25 Jan 2025 10:12:15 -0500
Subject: [PATCH 2/2] Fixed some things.

---
 src/grammar.y             |  3 +++
 src/lexer.c               |  1 +
 test/validation/test.bats | 13 +++++++++++++
 3 files changed, 17 insertions(+)

diff --git a/src/grammar.y b/src/grammar.y
index df7ddcc..f3f6890 100644
--- a/src/grammar.y
+++ b/src/grammar.y
@@ -27,6 +27,8 @@
 %token RGROUP
 %token SEP
 
+%token EXPSEP
+
 %token<strval> WORD
 %token<fval> NUM
 
@@ -50,6 +52,7 @@
 input:
     %empty
     | exp { root = $1; }
+    | input EXPSEP exp { root = $3; }
     ;
 
 
diff --git a/src/lexer.c b/src/lexer.c
index 6ac70cb..874a22d 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -112,6 +112,7 @@ int yylex() {
         case '(':  return LGROUP;
         case ')':  return RGROUP;
         case ',':  return SEP;
+        case ';': return EXPSEP;
         default:   fprintf(stderr, "Unexpected character: %c\n", c);
     }
 
diff --git a/test/validation/test.bats b/test/validation/test.bats
index 24ae0a0..313d21c 100644
--- a/test/validation/test.bats
+++ b/test/validation/test.bats
@@ -82,3 +82,16 @@ bin() { ./scl.out $1 | tail -n1; }
     run bin "-(-(1+2)*3)"
     [ "$output" = "= 9.000000" ]
 }
+
+@test "multiple expressions per line" {
+    run bin "1+1;2"
+    [ "$output" = "= 2.000000" ]
+}
+
+@test "variable definition" {
+    run bin "x = 1"
+    [ "$output" = "= 1.000000" ]
+
+    run bin "x = 1; x + 1"
+    [ "$output" = "= 2.000000" ]
+}