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[JEXL-411] Allow optional leading zeroes in floating point literals #409

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henrib merged 2 commits into from
Aug 12, 2026
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[JEXL-411] Allow optional leading zeroes in floating point literals #409

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c8cd40f
JEXL-411: Allow optional leading zeroes in floating point literals
NikRom5531 Aug 12, 2026
fecd3ad
JEXL-411: move isAllDigits to JexlParser;
henrib Aug 12, 2026
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3 changes: 3 additions & 0 deletions src/changes/changes.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,10 @@
<body>
<release version="3.7.1" date="YYYY-MM-DD" description="This is a feature and maintenance release. Java 8 or later is required.">
<!-- ADD -->
<action dev="henrib" type="add" issue="JEXL-467">IntelliJ and VSCode editors (TextMate bundle) support for JEXL.</action>
<!-- FIX -->
<action dev="henrib" type="fix" issue="JEXL-466">IllegalStateException parsing a template with string interpolation.</action>
<action dev="NikRom5531" due-to="Felix Rudolphi" type="fix" issue="JEXL-411">Leading zeroes in floating point numbers should be optional.</action>
<action dev="ggregory" type="fix" due-to="Gary Gregory">Pick up commons.jacoco.version from the parent POM.</action>
<action dev="ggregory" type="fix" due-to="Gary Gregory">Add messages when throwing NullPointerException.</action>
<!-- UPDATE -->
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23 changes: 23 additions & 0 deletions src/main/java/org/apache/commons/jexl3/parser/JexlParser.java
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Expand Up @@ -932,6 +932,29 @@ protected boolean isAmbiguousStatement(final int semicolon) {
return !getFeatures().supportsAmbiguousStatement();
}


/**
* Checks whether a token image is composed only of decimal digits.
* <p>Used to recognize a floating point literal with an omitted leading
* zero (e.g. {@code .1}) that is tokenized as {@code DOT DOT_IDENTIFIER}.</p>
*
* @param image the token image
* @return true if every character is a decimal digit
*/
protected boolean isAllDigits(final String image) {
int len = image != null ? image.length() : 0;
if (len == 0) {
return false;
}
for (int i = 0; i < len; ++i) {
final char c = image.charAt(i);
if (c < '0' || c > '9') {
return false;
}
}
return true;
}

/**
* Called by parser at end of node construction.
* <p>
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3 changes: 3 additions & 0 deletions src/main/java/org/apache/commons/jexl3/parser/Parser.jjt
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Expand Up @@ -1064,6 +1064,9 @@ void FloatLiteral() #NumberLiteral:
{
t=<FLOAT_LITERAL>
{ jjtThis.setReal(t.image); }
|
<DOT> t=<DOT_IDENTIFIER>

@henrib henrib Aug 12, 2026

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Nice trick :-)

{ if (!isAllDigits(t.image)) { throwParsingException(t); } jjtThis.setReal("." + t.image); }
}

void StringLiteral() :
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30 changes: 30 additions & 0 deletions src/test/java/org/apache/commons/jexl3/ArithmeticTest.java
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Expand Up @@ -2341,4 +2341,34 @@ void setOptions(final JexlOptions options) {
this.options = options;
}
}

@Test void testLeadingDotFloatLiteral() {
final JexlEngine jexl = new JexlBuilder().create();
final JexlContext jc = new MapContext();
// the exact case from JEXL-411
assertEquals(2.2d, jexl.createExpression("(1+.1)*2").evaluate(jc));
// the regression case that already worked
assertEquals(2.2d, jexl.createExpression("(1+0.1)*2").evaluate(jc));
// standalone and compound leading-dot literals
assertEquals(0.1d, jexl.createExpression(".1").evaluate(jc));
assertEquals(1.0d, jexl.createExpression(".5 + .5").evaluate(jc));
assertEquals(0.55d, jexl.createExpression(".55").evaluate(jc));
assertEquals(0.1d, jexl.createExpression("-.1 + .2").evaluate(jc));
assertEquals(-0.1d, jexl.createExpression(".1 + -.2").evaluate(jc));
assertEquals(0.1d, jexl.createExpression("-.1+.2").evaluate(jc));
assertEquals(-0.1d, jexl.createExpression(".1+-.2").evaluate(jc));
assertEquals(1.4d, jexl.createExpression(".5 - -.9").evaluate(jc));
assertEquals(0.4d, jexl.createExpression("-.5 - -.9").evaluate(jc));
assertEquals(-1.4d, jexl.createExpression("-.5+-.9").evaluate(jc));
// unary handling
assertEquals(-0.1d, jexl.createExpression("-.1").evaluate(jc));

@henrib henrib Aug 12, 2026

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Add the "+.1" test for completeness.

assertEquals(0.1d, jexl.createExpression("+.1").evaluate(jc));
// property / index access via a dot must keep working (not parsed as a float)
final List<Object> array = new java.util.ArrayList<>();
array.add("zero");
array.add("one");
jc.set("array", array);
assertEquals("zero", jexl.createExpression("array.0").evaluate(jc));
assertEquals("one", jexl.createExpression("array.1").evaluate(jc));

@henrib henrib Aug 12, 2026

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Add the 0/zero test.

}
}
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