From 4e8328135d78d6b3e1bc4571c3fea86c04ee7026 Mon Sep 17 00:00:00 2001
From: Kai Bublitz <kai.bublitz@posteo.de>
Date: Sat, 14 Feb 2026 15:37:48 +0100
Subject: [PATCH 1/2] fix: Fix parser syntax for numeric literals

The expression to parse numeric literals did not correctly match hex
numbers like "0xAB".
Also while analyzing the parser I found that it wrongfully accepted some
invalid expressions such as "123x456", which lead to an exception from
the num.parse call rather than the parser rejecting the input.

Updated the numericLiteral expression in the parser to
- match valid hex numbers by (digit() | anyOf('abcdefABCDEF')) instead
  of just digit().plus()
- prevent matching illegal hex expressions by separating the hex part
  always starting with "0x" and other numerical literal that may start
  with several digits.
- Also allowed the x to be uppercase "anyOf('xX')" in hex expressions,
  uppercase 0X123 is a valid literal for num.parse.

Extended the test case to include some more hex literals that were
previously not parsed correctly.
---
 lib/src/parser.dart        | 19 ++++++++++---------
 test/expressions_test.dart | 18 ++++++++++++------
 2 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/lib/src/parser.dart b/lib/src/parser.dart
index f709c3c..5f3161e 100644
--- a/lib/src/parser.dart
+++ b/lib/src/parser.dart
@@ -19,15 +19,16 @@ class ExpressionParser {
           .flatten()
           .map((v) => Identifier(v));
 
-  // Parse simple numeric literals: `12`, `3.4`, `.5`.
-  Parser<Literal> get numericLiteral => ((digit() | char('.')).and() &
-              (digit().star() &
-                  ((char('.') & digit().plus()) |
-                          (char('x') & digit().plus()) |
-                          (anyOf('Ee') &
-                              anyOf('+-').optional() &
-                              digit().plus()))
-                      .optional()))
+  // Parse simple numeric literals: `12`, `3.4`, `.5`, `0xAB`.
+  Parser<Literal> get numericLiteral =>
+      ((char('0') & anyOf('xX') & (digit() | anyOf('abcdefABCDEF')).plus()) |
+              (digit() | char('.')).and() &
+                  (digit().star() &
+                      ((char('.') & digit().plus()) |
+                              (anyOf('Ee') &
+                                  anyOf('+-').optional() &
+                                  digit().plus()))
+                          .optional()))
           .flatten()
           .map((v) {
         return Literal(num.parse(v), v);
diff --git a/test/expressions_test.dart b/test/expressions_test.dart
index d60f804..f1a9dd9 100644
--- a/test/expressions_test.dart
+++ b/test/expressions_test.dart
@@ -19,18 +19,24 @@ void main() {
     });
 
     test('numeric literal', () {
-      for (var v in ['134', '.5', '43.2', '1e3', '1E-3', '1e+0', '0x01']) {
+      for (var v in [
+        '134',
+        '.5',
+        '43.2',
+        '1e3',
+        '1E-3',
+        '1e+0',
+        '0x01',
+        '0xD3',
+        '0X1b'
+      ]) {
         var w = parser.numericLiteral.end().parse(v);
         expect(w is Success, isTrue, reason: 'Failed parsing `$v`');
         expect(w.value.value, num.parse(v));
         expect(w.value.raw, v);
       }
 
-      for (var v in [
-        '-134',
-        '.5.4',
-        '1e5E3',
-      ]) {
+      for (var v in ['-134', '.5.4', '1e5E3', '12x34']) {
         expect(parser.numericLiteral.end().parse(v) is Success, isFalse);
       }
     });

From e3c8f6c9d32a32ef1e4297a6de88a8e6e5a09cd3 Mon Sep 17 00:00:00 2001
From: Kai Bublitz <kai.bublitz@posteo.de>
Date: Sat, 14 Feb 2026 18:41:01 +0100
Subject: [PATCH 2/2] fix: Parser syntax for some more numeric expression

Another issue with the parser was that decimal point and "e"
could not be used in the same expression as they were parsed in different
"or" branches. Updated the parser to accept variations of valid
scientific notation, such as ".5e2" and "1.23e+4"
Notable exception are expression with trailing floating point such as
"2." or "1.e3". Those would be accepted by num.parse, but are not valid
numbers in dart.
---
 lib/src/parser.dart        | 7 ++-----
 test/expressions_test.dart | 8 ++++++--
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/lib/src/parser.dart b/lib/src/parser.dart
index 5f3161e..cc469e1 100644
--- a/lib/src/parser.dart
+++ b/lib/src/parser.dart
@@ -23,11 +23,8 @@ class ExpressionParser {
   Parser<Literal> get numericLiteral =>
       ((char('0') & anyOf('xX') & (digit() | anyOf('abcdefABCDEF')).plus()) |
               (digit() | char('.')).and() &
-                  (digit().star() &
-                      ((char('.') & digit().plus()) |
-                              (anyOf('Ee') &
-                                  anyOf('+-').optional() &
-                                  digit().plus()))
+                  ((digit().star() & (char('.') & digit().plus()).optional()) &
+                      (anyOf('Ee') & anyOf('+-').optional() & digit().plus())
                           .optional()))
           .flatten()
           .map((v) {
diff --git a/test/expressions_test.dart b/test/expressions_test.dart
index f1a9dd9..a6e7d6e 100644
--- a/test/expressions_test.dart
+++ b/test/expressions_test.dart
@@ -26,6 +26,9 @@ void main() {
         '1e3',
         '1E-3',
         '1e+0',
+        '.1e2',
+        '1.23e4',
+        '.6e-7',
         '0x01',
         '0xD3',
         '0X1b'
@@ -36,8 +39,9 @@ void main() {
         expect(w.value.raw, v);
       }
 
-      for (var v in ['-134', '.5.4', '1e5E3', '12x34']) {
-        expect(parser.numericLiteral.end().parse(v) is Success, isFalse);
+      for (var v in ['-134', '.5.4', '1e5E3', '5.', '12x34']) {
+        expect(parser.numericLiteral.end().parse(v) is Success, isFalse,
+            reason: 'Expected to fail parsing `$v`');
       }
     });