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|
const std = @import("std");
const tok = @import("tokenize.zig");
const symb = @import("symtable.zig");
const Iterator = tok.Iterator;
const Token = tok.Token;
const ParsingError = error{
InvalidExpression,
ExpectedExit,
ExpectedSemicolon,
ExpectedEqual,
ExpectedIdentifier,
InvalidStatement,
};
pub const Node = union(enum) {
Expr: NodeExpr,
Stmt: NodeStmt,
pub fn children(self: Node, allocator: std.mem.Allocator) ![]Node {
var childrenArray = std.ArrayList(Node).init(allocator);
defer childrenArray.deinit();
switch (self) {
.Expr => |expr| try childrenArray.appendSlice(try expr.children()),
.Stmt => |stmt| try childrenArray.appendSlice(try stmt.children()),
}
return try childrenArray.toOwnedSlice();
}
};
pub const NodeExpr = struct {
id: u32,
kind: ExprKind,
symtable: *symb.SymbolTable,
typ: ?symb.SymbType,
isConst: bool,
pub fn asNode(self: NodeExpr) Node {
return Node{ .Expr = self };
}
pub fn children(self: NodeExpr, allocator: std.mem.Allocator) ![]Node {
var childrenArray = std.ArrayList(Node).init(allocator);
defer childrenArray.deinit();
switch (self.kind) {
else => {},
}
return try childrenArray.toOwnedSlice();
}
};
pub const NodeStmt = struct {
id: u32,
kind: StmtKind,
symtable: *symb.SymbolTable,
pub fn asNode(self: NodeStmt) Node {
return Node{ .Stmt = self };
}
pub fn children(self: NodeStmt, allocator: std.mem.Allocator) ![]Node {
var childrenArray = std.ArrayList(Node).init(allocator);
defer childrenArray.deinit();
switch (self.kind) {
.exit => |exit| try childrenArray.append(exit.expr.asNode()),
.defValue => |value| try childrenArray.append(value.expr.asNode()),
.defVar => |variable| try childrenArray.append(variable.expr.asNode()),
.assignVar => |assign| try childrenArray.append(assign.expr.asNode()),
else => {},
}
return try childrenArray.toOwnedSlice();
}
};
pub const Parser = struct {
top: *symb.SymbolTable,
id: u32,
tokens: Iterator(Token),
allocator: std.mem.Allocator,
nodes: std.ArrayList(NodeStmt),
nextId: u32 = 1,
fn reserveId(self: *Parser) u32 {
defer self.nextId += 1;
return self.nextId;
}
pub fn init(allocator: std.mem.Allocator, tokens: []Token, symbolTable: *symb.SymbolTable) Parser {
return .{
.top = symbolTable,
.allocator = allocator,
.tokens = Iterator(Token).init(tokens),
.nodes = std.ArrayList(NodeStmt).init(allocator),
.id = 0,
};
}
pub fn deinit(self: *Parser) void {
self.nodes.deinit();
}
fn parseExpr(self: *Parser) !NodeExpr {
const kind = try switch (self.tokens.peek().?) {
.intLit => ExprKind{
.intLit = NodeIntlit{
.intlit = (try self.tokens.consume(.intLit)).?,
},
},
.ident => ExprKind{
.ident = NodeIdent{
.ident = (try self.tokens.consume(.ident)).?,
},
},
else => ParsingError.InvalidExpression,
};
return NodeExpr{
.id = self.reserveId(),
.kind = kind,
.isConst = kind.isConstant(),
.typ = null,
.symtable = self.top,
};
}
fn parseStmt(self: *Parser) !NodeStmt {
return switch (self.tokens.peek().?) {
.exit => try self.parseExit(),
.constant => try self.parseConstant(),
.variable => try self.parseVariable(),
.ident => try self.parseAssign(),
else => ParsingError.InvalidStatement,
};
}
fn parseAssign(self: *Parser) !NodeStmt {
const ident = (try self.tokens.consume(.ident)).?;
_ = try self.tokens.consume(.equal);
const expr = try self.parseExpr();
_ = try self.tokens.consume(.semiCol);
const kind = StmtKind{
.assignVar = NodeAssign{
.ident = ident,
.expr = expr,
},
};
return NodeStmt{
.id = self.reserveId(),
.kind = kind,
.symtable = self.top,
};
}
fn parseExit(self: *Parser) !NodeStmt {
_ = try self.tokens.consume(.exit);
const expr = try self.parseExpr();
_ = try self.tokens.consume(.semiCol);
const kind = StmtKind{ .exit = NodeExit{ .expr = expr } };
return NodeStmt{
.symtable = self.top,
.kind = kind,
.id = self.reserveId(),
};
}
fn parseVariable(self: *Parser) !NodeStmt {
_ = try self.tokens.consume(.variable);
const ident = (try self.tokens.consume(.ident)).?;
_ = try self.tokens.consume(.equal);
const expr = try self.parseExpr();
_ = try self.tokens.consume(.semiCol);
const kind = StmtKind{
.defVar = NodeVar{
.ident = ident,
.expr = expr,
},
};
return NodeStmt{
.id = self.reserveId(),
.kind = kind,
.symtable = self.top,
};
}
fn parseConstant(self: *Parser) !NodeStmt {
_ = try self.tokens.consume(.constant);
const ident = (try self.tokens.consume(.ident)).?;
_ = try self.tokens.consume(.equal);
const expr = try self.parseExpr();
_ = try self.tokens.consume(.semiCol);
const kind = StmtKind{
.defValue = NodeValue{
.ident = ident,
.expr = expr,
},
};
return NodeStmt{
.id = self.reserveId(),
.kind = kind,
.symtable = self.top,
};
}
pub fn parse(self: *Parser) ![]const NodeStmt {
while (self.tokens.peek()) |_|
try self.nodes.append(try self.parseStmt());
return self.nodes.items;
}
};
pub const NodeAssign = struct {
ident: Token,
expr: NodeExpr,
};
pub const NodeValue = struct {
ident: Token,
expr: NodeExpr,
};
pub const NodeVar = struct {
ident: Token,
expr: NodeExpr,
};
pub const NodeExit = struct {
expr: NodeExpr,
};
pub const NodeIntlit = struct {
intlit: Token,
};
pub const NodeIdent = struct {
ident: Token,
};
pub const StmtKind = union(enum) {
exit: NodeExit,
defValue: NodeValue,
defVar: NodeVar,
assignVar: NodeAssign,
};
pub const ExprKind = union(enum) {
intLit: NodeIntlit,
ident: NodeIdent,
pub fn isConstant(self: ExprKind) bool {
return switch (self) {
.intLit => true,
.ident => false,
};
}
};
test "Parser" {
const expect = std.testing.expect;
const src = "exit 120;";
var tokenizer = tok.Tokenizer.init(std.testing.allocator, src);
defer tokenizer.deinit();
const toks = try tokenizer.tokenize();
var parser = Parser.init(std.testing.allocator, toks);
defer parser.deinit();
const parseTree = try parser.parse();
const exp: []const NodeStmt = &[_]NodeStmt{NodeStmt{
.exit = NodeExit{
.expr = NodeExpr{
.intLit = NodeIntlit{
.intlit = Token{
.intLit = 120,
},
},
},
},
}};
for (parseTree, exp) |stmt, expStmt|
try expect(std.meta.eql(stmt, expStmt));
}
|
