add number tokens

This commit is contained in:
Luna 2019-05-31 22:08:41 -03:00
parent d1db7a0bd9
commit 69aa7b493d
3 changed files with 57 additions and 1 deletions

View file

@ -21,6 +21,9 @@ fn run(allocator: *Allocator, data: []u8) !void {
.Slice => |value| {
try value.printToken(stdout);
},
.Number => |value| {
try value.printToken(stdout);
},
}
hadError = false;

View file

@ -5,6 +5,10 @@ const main = @import("main.zig");
const TokenList = std.ArrayList(token.Token);
fn isDigit(char: u8) bool {
return char >= '0' and char <= '9';
}
pub const Scanner = struct {
source: []u8,
tokens: TokenList,
@ -55,6 +59,18 @@ pub const Scanner = struct {
});
}
/// Keep in mind Lox only has a single number type and that is a float one.
fn addNumberToken(self: *Scanner, ttype: token.TokenType, num: f32) !void {
try self.addToken(token.Token{
.Number = token.NumberToken.init(
ttype,
self.currentLexeme(),
self.line,
num,
),
});
}
fn addToken(
self: *Scanner,
tok: token.Token,
@ -114,6 +130,37 @@ pub const Scanner = struct {
);
}
fn peekNext(self: *Scanner) u8 {
if (self.current + 1 >= self.source.len) return 0;
return self.source[self.current + 1];
}
/// Consume a number
fn doNumber(self: *Scanner) !void {
while (isDigit(self.peek())) {
_ = self.advance();
}
// check if its a number like 12.34, where the '.' character
// exists and the one next to it is a digit.
if (self.peek() == '.' and isDigit(self.peekNext())) {
_ = self.advance();
while (isDigit(self.peek())) {
_ = self.advance();
}
}
// after going through all of the number, we can just use fmt.parseFloat
var num = try std.fmt.parseFloat(
f32,
self.source[self.start..self.current],
);
try self.addNumberToken(.NUMBER, num);
}
/// Scan through our tokens and add them to the Scanner's token list.
fn scanToken(self: *Scanner) !void {
var c = self.advance();
@ -154,7 +201,11 @@ pub const Scanner = struct {
'"' => try self.doString(),
else => {
try main.doError(self.line, "Unexpected character");
if (isDigit(c)) {
try self.doNumber();
} else {
try main.doError(self.line, "Unexpected character");
}
},
}
}

View file

@ -98,8 +98,10 @@ pub fn TokenFactory(
pub const SimpleToken = TokenFactory(void);
pub const SliceToken = TokenFactory([]u8);
pub const NumberToken = TokenFactory(f32);
pub const Token = union(enum) {
Simple: SimpleToken,
Slice: SliceToken,
Number: NumberToken,
};