From f146dac784325c9403499046f52f70e3596ae345 Mon Sep 17 00:00:00 2001
From: Nagi5Yeq <wu@x-nagi.com>
Date: Tue, 12 May 2020 01:52:49 +0800
Subject: initial commit

---
 Parser.y | 247 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 247 insertions(+)
 create mode 100644 Parser.y

(limited to 'Parser.y')

diff --git a/Parser.y b/Parser.y
new file mode 100644
index 0000000..bbad3fb
--- /dev/null
+++ b/Parser.y
@@ -0,0 +1,247 @@
+%language "c++"
+%require "3.2"
+
+%code requires {
+#include <string>
+
+namespace pcc {
+    class Driver;
+}
+}
+
+%param {pcc::Driver& driver}
+
+%code {
+#include "Driver.hh"
+}
+
+%define api.namespace {pcc}
+%define api.parser.class {Parser}
+%define api.value.type variant
+%define api.token.constructor
+%define parse.error verbose
+%define parse.assert
+
+%token COLON SEMICOLON COMMA DOT ASSIGN LBRACKET RBRACKET LPARENTHESIS RPARENTHESIS
+%token PROGRAM IDENTIFIER CONST VAR BEGINS ENDS FUNCTION
+%token IF THEN ELSE WHILE DO
+%token INTEGER BOOLEAN CHAR REAL STRING
+%token ADD SUB MUL REAL_DIV DIV MOD EXP LT LE GT GE EQ NE
+%token AND NOT OR XOR TRUE FALSE
+%token INTEGER_LITERAL REAL_LITERAL STRING_LITERAL
+
+%type <int> INTEGER_LITERAL
+%type <float> REAL_LITERAL
+%type <char*> STRING_LITERAL
+%type <char*> IDENTIFIER
+
+%%
+
+/* ==================[global part]================== */
+
+program
+    : program_decl global_decls function_decls
+    ;
+
+program_decl
+    : PROGRAM IDENTIFIER SEMICOLON
+    ;
+
+global_decls
+    : var_block
+    ;
+
+function_decls
+    : function_decls function_decl
+    |
+    ;
+
+/* ==================[var part]================== */
+
+var_block
+    : VAR var_decls SEMICOLON
+    ;
+
+var_decls
+    : var_decls SEMICOLON var_decl
+    | var_decl
+    ;
+
+var_decl
+    : vars COLON var_type
+    ;
+
+vars
+    : vars COMMA IDENTIFIER
+    | IDENTIFIER
+
+var_type
+    : INTEGER
+    | REAL
+    | BOOLEAN
+    | CHAR
+    | STRING
+    ;
+
+/* ==================[function part]================== */
+
+function_decl
+    : function_header function_body
+    ;
+
+function_header
+    : FUNCTION IDENTIFIER LPARENTHESIS var_decls RPARENTHESIS COLON var_type SEMICOLON
+    ;
+
+function_body
+    : var_block statement_block SEMICOLON
+    | statement_block SEMICOLON
+    ;
+
+/* ==================[statements part]================== */
+
+statements
+    : statements statement SEMICOLON
+    |
+    ;
+
+statement
+    : closed_statement
+    | open_statement
+    ;
+
+open_statement
+    : IF expression THEN statement
+    | IF expression THEN closed_statement ELSE open_statement
+    ;
+
+closed_statement
+    : normal_statement
+    | IF expression THEN closed_statement ELSE closed_statement
+    ;
+
+normal_statement
+    : statement_block
+    | empty_statement
+    | assign_statement
+    | while_statement
+    | expression_statement
+    ;
+
+statement_block
+    : BEGINS statements ENDS
+    ;
+
+empty_statement
+    :
+    ;
+
+assign_statement
+    : lvalue ASSIGN expression
+    ;
+
+while_statement
+    : WHILE expression DO statement
+    ;
+
+expression_statement
+    : function_call
+    ;
+
+/* ==================[expression part]================== */
+
+expression
+    : l1_expression l1_operator expression
+    | l1_expression
+    ;
+
+l1_expression
+    : l1_expression l2_operator l2_expression
+    | l2_expression
+    ;
+
+l2_expression
+    : l2_expression l3_operator l3_expression
+    | l3_expression
+    ;
+
+l3_expression
+    : l3_expression l4_operator l4_expression
+    | l4_expression
+
+l4_expression
+    : lvalue
+    | function_call
+    | literal
+    | LPARENTHESIS expression RPARENTHESIS
+    | l5_operator l4_expression
+    ;
+
+l1_operator
+    : LT
+    | LE
+    | GT
+    | GE
+    | EQ
+    | NE
+    ;
+
+l2_operator
+    : ADD
+    | SUB
+    | OR
+    | XOR
+    ;
+
+l3_operator
+    : MUL
+    | REAL_DIV
+    | DIV
+    | MOD
+    | AND
+    ;
+
+l4_operator
+    : EXP
+    ;
+
+l5_operator
+    : NOT
+    | ADD
+    | SUB
+    ;
+
+lvalue
+    : IDENTIFIER
+    | IDENTIFIER LBRACKET expression RBRACKET
+    | IDENTIFIER DOT IDENTIFIER
+    ;
+
+function_call
+    : IDENTIFIER LPARENTHESIS arguments RPARENTHESIS
+    | IDENTIFIER LPARENTHESIS RPARENTHESIS
+    ;
+
+arguments
+    : arguments COMMA expression
+    | expression
+    ;
+
+literal
+    : TRUE
+    | FALSE
+    | INTEGER_LITERAL
+    | REAL_LITERAL
+    | STRING_LITERAL
+    ;
+
+%%
+
+namespace pcc {
+
+    void Parser::error (const std::string& m)
+    {
+        std::cerr << m << '\n';
+    }
+
+}
-- 
cgit