feat: implement math in compiler

include/compiler/fzl_parser.h

@@ -11,6 +11,17 @@ typedef enum
   FZL_NODETYPE_BLOCK,
   FZL_NODETYPE_CALL,
   FZL_NODETYPE_LITERAL,
+  FZL_NODETYPE_IDENTIFIER,
+
+  FZL_NODETYPE_ADD,
+  FZL_NODETYPE_SUB,
+  FZL_NODETYPE_MUL,
+  FZL_NODETYPE_DIV,
+  FZL_NODETYPE_POW,
+  FZL_NODETYPE_MOD,
+
+  FZL_NODETYPE_UNARY_PLUS,
+  FZL_NODETYPE_UNARY_MINUS
 } fzl_nodetype_t;
 
 // AST node descriptor
@@ -23,11 +34,34 @@ typedef struct fzl_node
 
   union
   {
+    // Array of nested nodes (for blocks, etc)
     struct
     {
       struct fzl_node **entries;
       size_t entry_count;
     } list;
+
+    // Call data
+    struct
+    {
+      struct fzl_node *callee;
+
+      struct fzl_node **args;
+      size_t args_count;
+    } call;
+
+    // Binary operations
+    struct
+    {
+      struct fzl_node *left;
+      struct fzl_node *right;
+    } binary_op;
+
+    // Unary operations
+    struct
+    {
+      struct fzl_node *operand;
+    } unary_op;
   };
 } fzl_node_t;