parser: Implement variable assignment

This commit introduces variable assignment making it possible to
change a variable value. Example:

  myvar: i32 = 1;
  myvar = 2;

Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>
Co-authored-by: Carlos Maniero <carlos@maniero.me>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/ast.h b/src/ast.h
index 2bd700e..5095852 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -87,6 +87,12 @@ typedef struct ast_variable_declaration_t
   ast_node_t *value;
 } ast_variable_declaration_t;
 
+typedef struct ast_variable_assignment_t
+{
+  ast_identifier_t *identifier;
+  ast_node_t *expression;
+} ast_variable_assignment_t;
+
 typedef enum
 {
   AST_BINARY_OPERATION,
@@ -96,6 +102,7 @@ typedef enum
   AST_RETURN_STMT,
   AST_UNKOWN_NODE,
   AST_VARIABLE_DECLARATION,
+  AST_VARIABLE_ASSIGNMENT,
   AST_VARIABLE
 } ast_node_kind_t;
 
@@ -106,6 +113,7 @@ typedef union
   ast_literal_t literal;
   ast_return_stmt_t return_stmt;
   ast_variable_declaration_t variable_declaration;
+  ast_variable_assignment_t variable_assignment;
   ast_identifier_t identifier;
   ast_variable_t variable;
 } ast_node_data_t;