Pratt parsing, basic ast, decl parse const

new_ast.cpp

@@ -0,0 +1,186 @@
+
+// Lexer::interns::map::allocator - array allocator, resizing
+// Lexer::tokens                  - array allocator, resizing
+//
+// Parser::ast_arena                - arena for asts
+// Lexer::interns::string_allocator - arena for interns
+// 
+Intern_String keyword_const;
+Intern_String keyword_struct;
+Intern_String keyword_union;
+Intern_String keyword_enum;
+
+const U64 Parse_Ctx_ID = 115151;
+struct Parse_Ctx:Lexer{
+  Arena ast_arena;
+  Token empty_token;
+  S64 pt[256]; // precedence table
+  
+  void init(){
+    const S64 addp = 1;
+    const S64 mulp = 2;
+    pt[TK_Add] = addp;
+    pt[TK_Sub] = addp;
+    pt[TK_Div] = mulp;
+    pt[TK_Mul] = mulp;
+    
+    arena_init(&ast_arena);
+    lex_init(this);
+    keyword_const = intern_string(&interns, "const"_s);
+    keyword_struct= intern_string(&interns, "struct"_s);
+    keyword_union = intern_string(&interns, "union"_s);
+    keyword_enum  = intern_string(&interns, "enum"_s);
+    interns.first_keyword = keyword_const.str;
+    interns.last_keyword  = keyword_enum.str;
+  }
+};
+
+//-----------------------------------------------------------------------------
+// AST
+//-----------------------------------------------------------------------------
+enum Ast_Kind{
+  AK_None,
+  
+  AK_Expr_Str,
+  AK_Expr_Int,
+  AK_Expr_Ident,
+  AK_Expr_Binary,
+  
+  AK_Decl_Func,
+  AK_Decl_Func_Arg,
+  AK_Decl_Const,
+  
+  AK_Typespec_Ident,
+  AK_Typespec_Pointer,
+  AK_Typespec_Array,
+  AK_Typespec_Func
+};
+
+struct Ast{
+  Ast_Kind kind;
+  Token *pos;
+};
+
+struct Ast_Expr:Ast{
+  union{
+    Intern_String intern_val;
+    U64 int_val;
+    struct{
+      Token_Kind op;
+      Ast_Expr *left;
+      Ast_Expr *right;
+    } binary;
+  };
+};
+
+struct Ast_Typespec:Ast{
+  union{
+    Ast_Typespec *base;
+    Intern_String name;
+    struct{
+      Ast_Typespec *base;
+      Ast_Expr     *expr;
+    }arr;
+    struct{
+      Ast_Typespec *ret;
+      Array<Ast_Typespec*> args;
+    }func;
+  };
+};
+
+struct Ast_Decl:Ast{
+  Intern_String name;
+  union{
+    struct{
+      Ast_Typespec *typespec;
+      Intern_String name;
+      Ast_Expr     *expr;
+    }var;
+    struct{
+      Array<Ast_Decl*>   args;
+      Ast_Typespec *ret;
+    }func;
+  };
+};
+
+//-----------------------------------------------------------------------------
+// AST Constructors beginning with expressions
+//-----------------------------------------------------------------------------
+#define AST_NEW(T,ikind,ipos)                                 \
+Get_Ctx(Parse_Ctx);                                         \
+Ast_##T *result = exp_alloc_type(&ctx->ast_arena, Ast_##T); \
+result->kind    = ikind;                                    \
+result->pos     = ipos
+
+function Ast_Expr *
+ast_expr_string(Token *pos, Intern_String string){
+  AST_NEW(Expr, AK_Expr_Str, pos);
+  result->intern_val = string;
+  return result;
+}
+
+function Ast_Expr *
+ast_expr_identifier(Token *pos, Intern_String string){
+  AST_NEW(Expr, AK_Expr_Ident, pos);
+  result->intern_val = string;
+  return result;
+}
+
+function Ast_Expr *
+ast_expr_integer(Token *pos, S64 integer){
+  AST_NEW(Expr, AK_Expr_Int, pos);
+  result->int_val = integer;
+  return result;
+}
+
+function Ast_Expr *
+ast_expr_binary(Ast_Expr *left, Ast_Expr *right, Token *op){
+  AST_NEW(Expr, AK_Expr_Binary, op);
+  result->binary.op    = op->kind;
+  result->binary.left  = left;
+  result->binary.right = right;
+  return result;
+}
+
+//-----------------------------------------------------------------------------
+// Typespecs
+//-----------------------------------------------------------------------------
+function Ast_Typespec *
+ast_typespec_name(Token *pos, Intern_String name){
+  AST_NEW(Typespec, AK_Typespec_Ident, pos);
+  result->name = name;
+  return result;
+}
+
+function Ast_Typespec *
+ast_typespec_pointer(Token *pos, Ast_Typespec *base){
+  AST_NEW(Typespec, AK_Typespec_Pointer, pos);
+  result->base = base;
+  return result;
+}
+
+function Ast_Typespec *
+ast_typespec_array(Token *pos, Ast_Typespec *base, Ast_Expr *expr){
+  AST_NEW(Typespec, AK_Typespec_Array, pos);
+  result->arr.base = base;
+  result->arr.expr = expr;
+  return result;
+}
+
+//-----------------------------------------------------------------------------
+// Declarations
+//-----------------------------------------------------------------------------
+function Ast_Decl *
+ast_decl_func(Token *pos, Intern_String name){
+  AST_NEW(Decl, AK_Decl_Func, pos);
+  result->name = name;
+  return result;
+}
+
+function Ast_Decl *
+ast_decl_const(Token *pos, Intern_String name, Ast_Expr *expr){
+  AST_NEW(Decl, AK_Decl_Const, pos);
+  result->var.expr     = expr;
+  result->name         = name;
+  return result;
+}