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const std = @import("std");
const TokenError = error{UnknownToken};
pub const Token = union(enum) {
ret: []const u8,
intLit: i32,
binaryOp: u8,
semiCol,
nil,
};
/// Creates a tokenizer over a slice of typ
pub fn Iterator(comptime typ: type) type {
return struct {
items: []const typ,
index: usize = 0,
/// Initialize tokenizer with a slice
pub fn init(items: []const typ) Iterator(typ) {
return Iterator(typ){ .items = items };
}
/// Get current item
pub fn peek(self: Iterator(typ)) ?typ {
if (self.index >= self.items.len) return null;
return self.items[self.index];
}
/// Get current item and iterate index
pub fn consume(self: *Iterator(typ)) ?typ {
defer self.index += 1;
return self.peek();
}
/// Get current item and iterate index
pub const next = consume;
/// Skip over current item
pub fn skip(self: *Iterator(typ)) void {
self.index += 1;
}
};
}
/// Tokenizes a string of source code
pub const Tokenizer = struct {
src: Iterator(u8),
allocator: std.mem.Allocator,
toks: std.ArrayList(Token),
/// Initializes a string of source code
/// Deinitialize with Tokenizer.deinit()
pub fn init(allocator: std.mem.Allocator, src: []const u8) Tokenizer {
return Tokenizer{
.src = Iterator(u8).init(src),
.allocator = allocator,
.toks = std.ArrayList(Token).init(allocator),
};
}
/// Releases allocated memory
pub fn deinit(self: *Tokenizer) void {
self.toks.deinit();
}
/// Returns an ArrayList of tokens
pub fn tokenize(self: *Tokenizer) !std.ArrayList(Token) {
var str = std.ArrayList(u8).init(self.allocator);
defer str.deinit();
while (self.src.peek()) |char| {
switch (char) {
' ', '\n', '\t' => self.src.skip(),
'0'...'9' => {
while (std.ascii.isDigit(self.src.peek().?))
try str.append(self.src.consume().?);
const num: i32 = try std.fmt.parseInt(i32, str.items, 10);
try self.toks.append(.{ .intLit = num });
str.deinit();
str = std.ArrayList(u8).init(self.allocator);
},
'a'...'z', 'A'...'Z' => {
while (std.ascii.isAlphanumeric(self.src.peek().?))
try str.append(self.src.consume().?);
try self.toks.append(.{ .ret = try str.toOwnedSlice() });
str.deinit();
str = std.ArrayList(u8).init(self.allocator);
},
';' => {
self.src.skip();
try self.toks.append(.semiCol);
},
'+', '-', '*', '/' => try self.toks.append(.{ .binaryOp = self.src.consume().? }),
else => {},
}
}
return self.toks;
}
};
test "Tokenize" {
std.testing.log_level = std.log.Level.info;
const expect = std.testing.expect;
const testSource: []const u8 = "exit 120 + 150 - 260 * 12 / 5;";
var toks = Tokenizer.init(std.testing.allocator, testSource);
defer toks.deinit();
const arrtoks = try toks.tokenize();
const expected = &[_]Token{
.{ .ret = "exit" },
.{ .intLit = 120 },
.{ .binaryOp = '+' },
.{ .intLit = 150 },
.{ .binaryOp = '-' },
.{ .intLit = 260 },
.{ .binaryOp = '*' },
.{ .intLit = 12 },
.{ .binaryOp = '/' },
.{ .intLit = 5 },
.semiCol,
};
for (arrtoks.items, expected) |act, exp| {
switch (act) {
.ret => |v| {
try expect(std.mem.eql(u8, v, exp.ret));
std.testing.allocator.free(v);
},
.intLit => |v| try expect(v == exp.intLit),
.semiCol => |v| try expect(v == exp.semiCol),
.binaryOp => |v| try expect(v == exp.binaryOp),
else => {},
}
}
}
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