chore: small changes

CHANGELOG.md

@@ -24,7 +24,8 @@ Now in Zig!
 
 ## v0.0.1
 
-- [ ] 
+- [x] Lex integers & floating point numbers
+- [ ]
 
 
 

build.zig.zon

@@ -10,12 +10,12 @@
 
     // This is a [Semantic Version](https://semver.org/).
     // In a future version of Zig it will be used for package deduplication.
-    .version = "0.0.0",
+    .version = "0.0.1",
 
     // This field is optional.
     // This is currently advisory only; Zig does not yet do anything
     // with this value.
-    //.minimum_zig_version = "0.11.0",
+    .minimum_zig_version = "0.13.0",
 
     // This field is optional.
     // Each dependency must either provide a `url` and `hash`, or a `path`.

src/01_lexic/number.zig

@@ -110,7 +110,7 @@ fn integer(input: []const u8, cap: usize, start: usize) LexError!?LexReturn {
         },
         // if an `e` (exponential notiation) is found, lex that
         'e' => {
-            return null;
+            return scientific(input, cap, start, last_pos);
         },
         // otherwise return the current integer
         else => {
@@ -131,8 +131,8 @@ fn integer(input: []const u8, cap: usize, start: usize) LexError!?LexReturn {
 ///
 /// token_start: the position the current token started at
 /// decimal_point: the position of the decimal point `.`
-fn floating_point(input: []const u8, cap: usize, token_start: usize, decimal_point: usize) LexError!?LexReturn {
-    var current_pos = decimal_point + 1;
+fn floating_point(input: []const u8, cap: usize, token_start: usize, period_pos: usize) LexError!?LexReturn {
+    var current_pos = period_pos + 1;
 
     // there should be at least 1 digit after the period
     if (current_pos >= cap or !utils.is_decimal_digit(input[current_pos])) {
@@ -146,6 +146,12 @@ fn floating_point(input: []const u8, cap: usize, token_start: usize, decimal_poi
         current_pos += 1;
     }
 
+    // check if the current character is a `e`,
+    // if so lex a scientific number
+    if (current_pos < cap and input[current_pos] == 'e') {
+        return scientific(input, cap, token_start, current_pos);
+    }
+
     // return the matched fp number
     return .{
         Token.init(input[token_start..current_pos], TokenType.Float, token_start),
@@ -153,6 +159,38 @@ fn floating_point(input: []const u8, cap: usize, token_start: usize, decimal_poi
     };
 }
 
+/// exp_pos is the position at the `e` character
+fn scientific(input: []const u8, cap: usize, token_start: usize, exp_pos: usize) LexError!?LexReturn {
+    var current_pos = exp_pos + 1;
+
+    // expect `+` or `-`
+    if (current_pos >= cap) {
+        return LexError.IncompleteScientificNumber;
+    }
+    const sign_char = input[current_pos];
+    if (sign_char != '+' and sign_char != '-') {
+        return LexError.IncompleteScientificNumber;
+    }
+    current_pos += 1;
+    const digits_start = current_pos;
+
+    // lex at least 1 digit
+    while (current_pos < cap and utils.is_decimal_digit(input[current_pos])) {
+        current_pos += 1;
+    }
+
+    // if there is no difference, no extra digits were lexed.
+    if (digits_start == current_pos) {
+        return LexError.IncompleteScientificNumber;
+    }
+
+    // return the scientific number
+    return .{
+        Token.init(input[token_start..current_pos], TokenType.Float, token_start),
+        current_pos,
+    };
+}
+
 test "int lexer 1" {
     const input = "322   ";
     const result = try integer(input, input.len, 0);
@@ -393,3 +431,61 @@ test "should fail on incomplete fp number" {
 
     try std.testing.expect(false);
 }
+
+test "should lex scientific number" {
+    const input = "42e+3";
+    const result = try lex(input, input.len, 0);
+
+    if (result) |tuple| {
+        const r = tuple[0];
+        try std.testing.expectEqualDeep("42e+3", r.value);
+    } else {
+        try std.testing.expect(false);
+    }
+}
+
+test "should fail on incomplete scientific number" {
+    const input = "123e";
+    const result = lex(input, input.len, 0) catch |err| {
+        try std.testing.expect(err == token.LexError.IncompleteScientificNumber);
+        return;
+    };
+
+    if (result) |tuple| {
+        const r = tuple[0];
+        std.debug.print("{s}\n", .{r.value});
+    } else {
+        std.debug.print("nil returned", .{});
+    }
+
+    try std.testing.expect(false);
+}
+
+test "should fail on incomplete scientific number 2" {
+    const input = "123e+";
+    const result = lex(input, input.len, 0) catch |err| {
+        try std.testing.expect(err == token.LexError.IncompleteScientificNumber);
+        return;
+    };
+
+    if (result) |tuple| {
+        const r = tuple[0];
+        std.debug.print("{s}\n", .{r.value});
+    } else {
+        std.debug.print("nil returned", .{});
+    }
+
+    try std.testing.expect(false);
+}
+
+test "should lex floating scientific number" {
+    const input = "0.58e+3";
+    const result = try lex(input, input.len, 0);
+
+    if (result) |tuple| {
+        const r = tuple[0];
+        try std.testing.expectEqualDeep("0.58e+3", r.value);
+    } else {
+        try std.testing.expect(false);
+    }
+}

src/01_lexic/token.zig

@@ -21,4 +21,5 @@ pub const LexError = error{
     LeadingZero,
     Incomplete,
     IncompleteFloatingNumber,
+    IncompleteScientificNumber,
 };