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parser.d
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/// 再帰下降構文解析器
module parser;
import std.stdio : stderr;
import token;
import util;
import sema;
// BNFじみた表記になっているが特にBNFとしては意味のないメモ書き
// <func> ::= <compound_stmt>
// <compound_stmt> ::= {<stmt>}
// <stmt> ::= <if> | <assign>
// <if> ::= if (<assign>) <stmt> [else <stmt>]
// <assign> ::= <logicalOr> | <logicalOr> = <logicalOr>
// <logicalOr> ::= <logicalAnd> | <logicalAnd> || <logicalAnd>
// <logicalAnd> ::= <rel> | <rel> && <rel>
// <rel> ::= <add> | <add> < <add>
// <add> ::= <mul> | <mul> + <mul>
// <mul> ::= <term> | <term> * <term>
// <term> ::= <assign> | <NUM> | <IDENTIFIER>
public:
enum NodeType : int
{
LESS_THAN = '<',
ADD = '+',
SUB = '-',
MUL = '*',
DIV = '/',
ASSIGN = '=',
NUM = 256,
IDENTIFIER,
STRING,
VARIABLE_DEFINITION,
LOCAL_VARIABLE,
GLOBAL_VARIABLE,
DEREFERENCE,
RETURN,
IF,
FOR,
COMPOUND_STATEMENT,
EXPRESSION_STATEMENT,
// 複文式とか言われるGNU拡張。
// ({})の中に複数の文を書けて、returnした結果が式の値になる
STATEMENT_EXPRESSION,
CALL,
FUNCTION,
LOGICAL_AND,
LOGICAL_OR,
ADDRESS,
SIZEOF,
EQUAL,
NOT_EQUAL,
DO_WHILE,
NODE,
ALIGNOF,
NULL,
}
struct Node
{
NodeType op;
// (op == LOGICAL_AND, LOGICAL_OR, LESS_THAN, ADD, SUB, MUL, DIV, ASSIGN)
Node* lhs = null;
Node* rhs = null;
int val; // 値リテラル (op == NUM)
Node* expr; // 式 (op == EXPRESSION_STATEMENT, RETURN)
Node[] statements; // 文 (op == COMPOUND_STATEMENT)
bool is_extern;
string name; // 変数名または関数名 (op == IDENTIFIER, FUNCTION)
ubyte[] data;
// typeの値によって役割が変わる
// function (<args>){<body>} (op == FUNCTION)
// if (<cond>) <then> else <els> (op == IF)
// for (<init>;<cond>;<inc>) <body> (op == FOR)
// function(<args>) (op == CALL)
Node* initalize;
Node* cond;
Node* inc;
Node* then;
Node* els;
Node* bdy;
Node[] args;
// FUNCTIONノード用
size_t stacksize;
Variable[] globals;
// 変数関連ノード用
size_t offset;
Type* type;
}
Node[] parse(Token[] tokens)
{
size_t i;
Node[] functions;
while (tokens[i].type != TokenType.EOF)
{
functions ~= *topLevel(tokens, i);
}
return functions;
}
private:
void expect(char c, Token[] tokens, ref size_t i)
{
expect(cast(TokenType) c, tokens, i);
}
void expect(TokenType t, Token[] tokens, ref size_t i)
{
if (tokens[i].type != t)
{
error("Line %d: %s (%s) expected, but got %s (%s)", tokens[i].lineno,
cast(char) t, t, tokens[i].input, tokens[i].type);
}
i++;
}
bool consume(char c, Token[] tokens, ref size_t i)
{
return consume(cast(TokenType) c, tokens, i);
}
bool consume(TokenType type, Token[] tokens, ref size_t i)
{
if (tokens[i].type == type)
{
i++;
return true;
}
return false;
}
Type* getType(Token t)
{
switch (t.type)
{
case TokenType.INT:
return new Type(TypeName.INT);
case TokenType.CHAR:
return new Type(TypeName.CHAR);
default:
return null;
}
}
Node* newBinOp(NodeType op, Node* lhs, Node* rhs)
{
Node* node = new Node();
node.op = op;
node.lhs = lhs;
node.rhs = rhs;
return node;
}
Node* newExpr(NodeType op, Node* expr)
{
Node* node = new Node();
node.op = op;
node.expr = expr;
return node;
}
// 関数とグローバル変数
Node* topLevel(Token[] tokens, ref size_t i)
{
bool is_extern = consume(TokenType.EXTERN, tokens, i);
Type* ty = type(tokens, i);
if (!ty)
{
error("Typename expected, but got %s", tokens[i].input);
}
if (tokens[i].type != TokenType.IDENTIFIER)
{
error("Function or Variable name expected, but got %s", tokens[i].input);
}
string name = tokens[i].name;
i++;
// 関数
if (consume('(', tokens, i))
{
Node* n = new Node();
n.op = NodeType.FUNCTION;
n.type = ty;
auto t = tokens[i];
n.name = name;
if (!consume(')', tokens, i))
{
n.args ~= *param(tokens, i);
while (consume(',', tokens, i))
{
n.args ~= *param(tokens, i);
}
expect(')', tokens, i);
}
expect('{', tokens, i);
n.bdy = compound_stmt(tokens, i);
return n;
}
// グローバル変数
Node* n = new Node();
n.op = NodeType.VARIABLE_DEFINITION;
n.type = readArray(ty, tokens, i);
n.name = name;
if (is_extern)
{
n.is_extern = true;
}
else
{
n.data = new ubyte[](size_of(*n.type));
}
expect(';', tokens, i);
return n;
}
// 複数の文
Node* compound_stmt(Token[] tokens, ref size_t i)
{
Node* n = new Node();
n.op = NodeType.COMPOUND_STATEMENT;
while (!consume('}', tokens, i))
{
n.statements ~= *stmt(tokens, i);
}
return n;
}
// 制御構造でない文
Node* expressionStatement(Token[] tokens, ref size_t i)
{
Node* node = newExpr(NodeType.EXPRESSION_STATEMENT, assign(tokens, i));
expect(';', tokens, i);
return node;
}
Node* param(Token[] tokens, ref size_t i)
{
Node* node = new Node();
node.op = NodeType.VARIABLE_DEFINITION;
node.type = type(tokens, i);
if (tokens[i].type != TokenType.IDENTIFIER)
{
error("Parameter name expected, but got %s", tokens[i].input);
}
node.name = tokens[i].name;
i++;
return node;
}
// 変数宣言
Node* declaration(Token[] tokens, ref size_t i)
{
Node* node = new Node();
node.op = NodeType.VARIABLE_DEFINITION;
// 型名
node.type = type(tokens, i);
// 変数名
if (tokens[i].type != TokenType.IDENTIFIER)
{
error("Variable name expected, but got %s", tokens[i].input);
}
node.name = tokens[i].name;
i++;
// 配列
node.type = readArray(node.type, tokens, i);
// 初期化
if (consume('=', tokens, i))
{
node.initalize = assign(tokens, i);
}
expect(';', tokens, i);
return node;
}
Type* type(Token[] tokens, ref size_t i)
{
Type* ty = getType(tokens[i]);
if (!ty)
{
error("Type name expected, but got %s", tokens[i].input);
}
i++;
while (consume('*', tokens, i))
{
ty = () {
Type* t = new Type();
t.type = TypeName.POINTER;
t.pointer_to = ty;
return t;
}();
}
return ty;
}
Type* readArray(Type* type, Token[] tokens, ref size_t i)
{
Node[] array_size;
while (consume('[', tokens, i))
{
Node* length = primary(tokens, i);
if (length.op != NodeType.NUM)
{
error("Number expected, but got %s", length.type);
}
array_size ~= *length;
expect(']', tokens, i);
}
foreach_reverse (length; array_size)
{
type = () {
Type* t = new Type();
t.type = TypeName.ARRAY;
t.array_of = type;
t.array_length = length.val;
return t;
}();
}
return type;
}
// 文
Node* stmt(Token[] tokens, ref size_t i)
{
Node* node = new Node();
switch (tokens[i].type)
{
case TokenType.SEMICOLONE:
i++;
return new Node(NodeType.NULL);
case TokenType.IF:
i++;
node.op = NodeType.IF;
expect('(', tokens, i);
node.cond = assign(tokens, i);
expect(')', tokens, i);
node.then = stmt(tokens, i);
if (consume(TokenType.ELSE, tokens, i))
{
node.els = stmt(tokens, i);
}
return node;
case TokenType.FOR:
i++;
node.op = NodeType.FOR;
expect('(', tokens, i);
if (getType(tokens[i]))
{
node.initalize = declaration(tokens, i);
}
else
{
node.initalize = expressionStatement(tokens, i);
}
node.cond = assign(tokens, i);
expect(';', tokens, i);
// スコープをしぼる
node.inc = newExpr(NodeType.EXPRESSION_STATEMENT, assign(tokens, i));
expect(')', tokens, i);
node.bdy = stmt(tokens, i);
return node;
case TokenType.WHILE:
i++;
node.op = NodeType.FOR;
node.initalize = new Node(NodeType.NULL);
node.inc = new Node(NodeType.NULL);
expect('(', tokens, i);
node.cond = assign(tokens, i);
expect(')', tokens, i);
node.bdy = stmt(tokens, i);
return node;
case TokenType.DO:
i++;
node.op = NodeType.DO_WHILE;
node.bdy = stmt(tokens, i);
expect(TokenType.WHILE, tokens, i);
expect('(', tokens, i);
node.cond = assign(tokens, i);
expect(')', tokens, i);
expect(';', tokens, i);
return node;
case TokenType.RETURN:
i++;
Node* n = newExpr(NodeType.RETURN, assign(tokens, i));
expect(';', tokens, i);
return n;
case TokenType.LEFT_BRACE:
i++;
node.op = NodeType.COMPOUND_STATEMENT;
while (!consume('}', tokens, i))
{
node.statements ~= *stmt(tokens, i);
}
return node;
case TokenType.INT:
case TokenType.CHAR:
return declaration(tokens, i);
default:
return expressionStatement(tokens, i);
}
}
// 変数への代入と式
Node* assign(Token[] tokens, ref size_t i)
{
Node* lhs = logicalOr(tokens, i);
if (consume('=', tokens, i))
{
return newBinOp(NodeType.ASSIGN, lhs, logicalOr(tokens, i));
}
return lhs;
}
// Cでは論理演算子の間に優先順位がある
// or式
Node* logicalOr(Token[] tokens, ref size_t i)
{
Node* lhs = logicalAnd(tokens, i);
while (true)
{
TokenType op = tokens[i].type;
if (op != TokenType.LOGICAL_OR)
{
return lhs;
}
i++;
lhs = newBinOp(NodeType.LOGICAL_OR, lhs, logicalAnd(tokens, i));
}
}
// and式
Node* logicalAnd(Token[] tokens, ref size_t i)
{
Node* lhs = equality(tokens, i);
while (true)
{
TokenType op = tokens[i].type;
if (op != TokenType.LOGICAL_AND)
{
return lhs;
}
i++;
lhs = newBinOp(NodeType.LOGICAL_AND, lhs, equality(tokens, i));
}
}
// 等値判定
Node* equality(Token[] tokens, ref size_t i)
{
Node* lhs = rel(tokens, i);
while (true)
{
TokenType op = tokens[i].type;
if (op == TokenType.EQUAL)
{
i++;
lhs = newBinOp(NodeType.EQUAL, lhs, rel(tokens, i));
continue;
}
if (op == TokenType.NOT_EQUAL)
{
i++;
lhs = newBinOp(NodeType.NOT_EQUAL, lhs, rel(tokens, i));
continue;
}
return lhs;
}
}
// 大小比較
Node* rel(Token[] tokens, ref size_t i)
{
// 向きを < (less than)に統一する
Node* lhs = add(tokens, i);
while (true)
{
TokenType op = tokens[i].type;
if (op == TokenType.LESS_THAN)
{
i++;
lhs = newBinOp(NodeType.LESS_THAN, lhs, add(tokens, i));
continue;
}
if (op == TokenType.GREATER_THAN)
{
i++;
lhs = newBinOp(NodeType.LESS_THAN, add(tokens, i), lhs);
continue;
}
return lhs;
}
}
// 加算式
Node* add(Token[] tokens, ref size_t i)
{
Node* lhs = mul(tokens, i);
while (true)
{
TokenType op = tokens[i].type;
if (op != TokenType.ADD && op != TokenType.SUB)
{
return lhs;
}
i++;
lhs = newBinOp(cast(NodeType) op, lhs, mul(tokens, i));
}
}
// 乗算式
Node* mul(Token[] tokens, ref size_t i)
{
Node* lhs = unary(tokens, i);
while (true)
{
TokenType op = tokens[i].type;
if (op != TokenType.ASTERISK && op != TokenType.DIV)
{
return lhs;
}
i++;
lhs = newBinOp(cast(NodeType) op, lhs, unary(tokens, i));
}
}
Node* unary(Token[] tokens, ref size_t i)
{
if (consume('*', tokens, i))
{
return newExpr(NodeType.DEREFERENCE, mul(tokens, i));
}
if (consume('&', tokens, i))
{
return newExpr(NodeType.ADDRESS, mul(tokens, i));
}
if (consume(TokenType.SIZEOF, tokens, i))
{
return newExpr(NodeType.SIZEOF, unary(tokens, i));
}
if (consume(TokenType.ALIGNOF, tokens, i))
{
return newExpr(NodeType.ALIGNOF, unary(tokens, i));
}
return postfix(tokens, i);
}
// ary[x][y] -> *(ary + x)[y] -> *(*(ary + x) + y)
Node* postfix(Token[] tokens, ref size_t i)
{
Node* lhs = primary(tokens, i);
while (consume('[', tokens, i))
{
lhs = newExpr(NodeType.DEREFERENCE, newBinOp(NodeType.ADD, lhs, assign(tokens, i)));
expect(']', tokens, i);
}
return lhs;
}
// 項
Node* primary(Token[] tokens, ref size_t i)
{
if (tokens[i].type == TokenType.LEFT_PARENTHESE)
{
i++;
if (consume('{', tokens, i))
{
Node* n = new Node();
n.op = NodeType.STATEMENT_EXPRESSION;
n.bdy = compound_stmt(tokens, i);
expect(')', tokens, i);
return n;
}
else
{
Node* n = assign(tokens, i);
expect(')', tokens, i);
return n;
}
}
if (tokens[i].type == TokenType.NUM)
{
Node* n = new Node();
n.op = NodeType.NUM;
n.type = new Type(TypeName.INT);
n.val = tokens[i].val;
i++;
return n;
}
if (tokens[i].type == TokenType.IDENTIFIER)
{
Node* n = new Node();
n.name = tokens[i].name;
i++;
if (!consume('(', tokens, i))
{
n.op = NodeType.IDENTIFIER;
return n;
}
n.op = NodeType.CALL;
if (consume(')', tokens, i))
{
return n;
}
n.args ~= *assign(tokens, i);
while (consume(',', tokens, i))
{
n.args ~= *assign(tokens, i);
}
expect(')', tokens, i);
return n;
}
if (tokens[i].type == TokenType.STRING)
{
Node* n = new Node();
n.op = NodeType.STRING;
n.type = () {
Type* t = new Type();
t.type = TypeName.ARRAY;
t.array_of = new Type(TypeName.CHAR);
t.array_length = tokens[i].str.length;
return t;
}();
n.data = cast(ubyte[])(tokens[i].str ~ '\0');
i++;
return n;
}
error("Number expected, but got %s", tokens[i].input);
assert(0);
}