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[#9] Added Null-Coalescing and Ternary-conditional operators #10

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3c477b8
[#9] Added Null-Coalescing and Ternary-conditional operators
Jul 23, 2026
40a8438
[#9] Added unit-test
Jul 28, 2026
daab205
Merge remote-tracking branch 'https/develop' into 9-adding-null-based…
Jul 28, 2026
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119 changes: 110 additions & 9 deletions ....esi.xtext.expressions.tests/src/nl/esi/xtext/expressions/tests/CustomConverterTest.xtend
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
package nl.esi.xtext.expressions.tests

import com.google.inject.Inject
import java.net.URI
import java.util.Optional
import java.util.UUID
import nl.esi.xtext.expressions.conversion.IExpressionConverter
Expand All @@ -22,6 +23,7 @@ import org.eclipse.xtext.resource.XtextResourceSet
import org.junit.jupiter.api.Assertions
import org.junit.jupiter.api.BeforeEach
import org.junit.jupiter.api.Test
import java.net.URISyntaxException

/**
* Tests that custom converters can be registered and used to handle
Expand All @@ -46,10 +48,12 @@ class CustomConverterTest extends ExpressionEvaluatorTestBase {
var handler = registry.getURIHandler()
resourceSet.URIConverter?.URIHandlers?.add(0, handler)

// Register the sample library
// Register the sample libraries
registry.addLibraryFunctions(SampleLibraryWithUUID)
// Add the converter
registry.addLibraryFunctions(SampleLibraryWithURI)
// Add the converters
registry.addConverter(new UUIDConverter)
registry.addConverter(new URIConverter)
initialized = true

}
Expand All @@ -73,7 +77,11 @@ class CustomConverterTest extends ExpressionEvaluatorTestBase {
Assertions.assertAll(
[Assertions.assertTrue(content.contains("function uuid fromString("), "fromString")],
[Assertions.assertTrue(content.contains("function string uuidToString("), "uuidToString")],
[Assertions.assertTrue(content.contains("function bool isValidUUID("), "isValidUUID")]
[Assertions.assertTrue(content.contains("function bool isValidUUID("), "isValidUUID")],
[Assertions.assertTrue(content.contains("function string getScheme("), "getScheme")],
[Assertions.assertTrue(content.contains("function string getHost("), "getHost")],
[Assertions.assertTrue(content.contains("function int getPort("), "getPort")],
[Assertions.assertTrue(content.contains("function string getPath("), "getPath")]
)
}

Expand All @@ -92,9 +100,13 @@ class CustomConverterTest extends ExpressionEvaluatorTestBase {
@Test
def void call_uuidToString_convertsUUIDToString() {
assertEval('''
type uuid based on string

uuid id = "550e8400-e29b-41d4-a716-446655440000"
string result = "550e8400-e29b-41d4-a716-446655440000"
''', '''
type uuid based on string

uuid id = "550e8400-e29b-41d4-a716-446655440000"
string result = uuidToString(id)
''')
Expand Down Expand Up @@ -126,6 +138,28 @@ class CustomConverterTest extends ExpressionEvaluatorTestBase {
bool result = isValidUUID("")
''')
}

@Test
def void call_getComponents_getsComponentsOfAnURI() {
assertEval('''
type uri based on string

uri github = "https://github.com:443/TNO/XPlus"
string scheme = "https"
string host = "github.com"
int port = 443
string path = "/TNO/XPlus"
''', '''
type uri based on string

uri github = "https://github.com:443/TNO/XPlus"
string scheme = getScheme(github)
string host = getHost(github)
int port = getPort(github)
string path = getPath(github)
''')
}

}

/**
Expand Down Expand Up @@ -198,15 +232,82 @@ class UUIDConverter implements IExpressionConverter {

override Optional<Expression> toExpression(Object object, Type type) {
// Only convert UUID objects
if (!(object instanceof UUID)){
if (object instanceof UUID){
// Check if target type is string-like
var context = IEvaluationContext.EMPTY;
val result = context.toExpression(object.toString)
if (result !== null) {
return Optional.of(result)
}
}
return Optional.empty()
}
}

/**
* Sample library with URI-related functions.
* This demonstrates how a library might use custom Java types
* that require converters to work with the expression language.
*/
class SampleLibraryWithURI {
def static getScheme(URI uri) {
uri.scheme
}

def static getHost(URI uri) {
uri.host
}

def static getPort(URI uri) {
uri.port
}

def static getPath(URI uri) {
uri.path
}
}

/**
* Custom converter for UUID type.
* Converts between Expression (string literals) and java.util.UUID objects.
*/
class URIConverter implements IExpressionConverter {

override Optional<Object> toObject(Expression expression, Class<?> targetType) {
// Only convert to URI type
if (!targetType.equals(URI)){
return Optional.empty()
}

// Check if target type is string-like

// Handle null
if (expression === null) {
return Optional.empty()
}

var context = IEvaluationContext.EMPTY;
val result = context.toExpression(object.toString)
if (result !== null) {
return Optional.of(result)
// Convert string expression to URI
try {
val value = context.asString(expression)
if (value === null || value.empty) {
return Optional.empty()
}
val uri = new URI(value)
return Optional.of(uri)
} catch (URISyntaxException e) {
// Invalid URI format
return Optional.empty()
}
}

override Optional<Expression> toExpression(Object object, Type type) {
// Only convert URI objects
if (object instanceof URI) {
// Check if target type is string-like
var context = IEvaluationContext.EMPTY;
val result = context.toExpression(object.toString)
if (result !== null) {
return Optional.of(result)
}
}
return Optional.empty()
}
Expand Down
24 changes: 14 additions & 10 deletions ...t.expressions.tests/src/nl/esi/xtext/expressions/tests/ExpressionEvaluatorBasicTest.xtend
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Original file line number Diff line number Diff line change
Expand Up @@ -111,15 +111,19 @@ class ExpressionEvaluatorBasicTest extends ExpressionEvaluatorTestBase {
assertEval('''
bool v_eq_null_1 = true
bool v_eq_null_2 = false
bool v_eq_null_3 = false

bool v_neq_null_1 = false
bool v_neq_null_2 = true
bool v_neq_null_3 = true
''', '''
bool v_eq_null_1 = null == null
bool v_eq_null_2 = null == 1
bool v_eq_null_3 = "" == null

bool v_neq_null_1 = null != null
bool v_neq_null_2 = null != 1
bool v_neq_null_3 = "" != null
''')
}

Expand Down Expand Up @@ -218,28 +222,28 @@ class ExpressionEvaluatorBasicTest extends ExpressionEvaluatorTestBase {
real v_add_real_1 = 3.3
real v_add_real_2 = 6.6

int v_sub_real_1 = 1.1
int v_sub_real_2 = - 2.2
int v_sub_real_3 = 1.3
real v_sub_real_1 = 1.1
real v_sub_real_2 = - 2.2
real v_sub_real_3 = 1.3
''', '''
real v_add_real_1 = 1.1 + 2.2
real v_add_real_2 = 1.1 + 2.2 + 3.3

int v_sub_real_1 = 2.2 - 1.1
int v_sub_real_2 = 2.2 - 4.4
int v_sub_real_3 = 10.10 - 5.5 - 3.3
real v_sub_real_1 = 2.2 - 1.1
real v_sub_real_2 = 2.2 - 4.4
real v_sub_real_3 = 10.10 - 5.5 - 3.3
''')
}

@Test
def void level4String() {
// Resolved variable
assertEval('''
real v_add_string_1 = "aabb"
real v_add_string_2 = "aabbcc"
string v_add_string_1 = "aabb"
string v_add_string_2 = "aabbcc"
''', '''
real v_add_string_1 = "aa" + "bb"
real v_add_string_2 = "aa" + "bb" + "cc"
string v_add_string_1 = "aa" + "bb"
string v_add_string_2 = "aa" + "bb" + "cc"
''')
}
}
130 changes: 128 additions & 2 deletions ...expressions.tests/src/nl/esi/xtext/expressions/tests/ExpressionEvaluatorComplexTest.xtend
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Original file line number Diff line number Diff line change
Expand Up @@ -305,7 +305,7 @@ class ExpressionEvaluatorComplexTest extends ExpressionEvaluatorTestBase {
@Test
def void expressionMinus() {
assertEval('int a = -1', 'int a = -1')
assertEval('int a = -1.0', 'int a = -1.0')
assertEval('real a = -1.0', 'real a = -1.0')
}

@Test
Expand Down Expand Up @@ -337,7 +337,7 @@ class ExpressionEvaluatorComplexTest extends ExpressionEvaluatorTestBase {
@Test
def void expressionPlus() {
assertEval('int a = 1', 'int a = +1')
assertEval('int a = 1.0', 'int a = +1.0')
assertEval('real a = 1.0', 'real a = +1.0')

// Resolved variable
assertEval('''
Expand All @@ -357,4 +357,130 @@ class ExpressionEvaluatorComplexTest extends ExpressionEvaluatorTestBase {
int b = +a
''')
}

@Test
def void expressionNullCoalescing() {
assertEval('int a = 1', 'int a = 1 ?? 2')
assertEval('real a = 2.0', 'real a = null ?? 2.0')

// Resolved variable
assertEval('''
int a = 1
int b = null
int c = 1

int x = null
int y = 5
int z = 5
''', '''
int a = 1
int b = null
int c = a ?? b

int x = null
int y = 5
int z = x ?? y
''')

// Unresolved variable
assertEval('''
int a
int b = 1
int c = a ?? 1

int x = 4
int y
int z = 4
''', '''
int a
int b = 1
int c = a ?? b

int x = 4
int y
int z = x ?? y
''')
}

@Test
def void expressionConditional() {
assertEval('int a = 1', 'int a = true ? 1 : 2')
assertEval('real a = 2.0', 'real a = false ? null : 2.0')

// Resolved variable
assertEval('''
bool a = true
int b = 1
int c = 2
int d = 1

bool f = true
int g = null
int h = 2
int i = null

bool j = false
int k = 1
int l = null
int m = null

bool w = null
int x = 1
int y = 2
int z = null ? 1 : 2
''', '''
bool a = true
int b = 1
int c = 2
int d = a ? b : c

bool f = true
int g = null
int h = 2
int i = f ? g : h

bool j = false
int k = 1
int l = null
int m = j ? k : l

bool w = null
int x = 1
int y = 2
int z = w ? x : y
''')

// Unresolved variable
assertEval('''
bool a
int b = 1
int c = 2
int d = a ? 1 : 2

bool f = true
int g
int h = 2
int i = g

bool j = false
int k = 1
int l
int m = l
''', '''
bool a
int b = 1
int c = 2
int d = a ? b : c

bool f = true
int g
int h = 2
int i = f ? g : h

bool j = false
int k = 1
int l
int m = j ? k : l
''')
}
}
2 changes: 1 addition & 1 deletion ...xpressions.tests/src/nl/esi/xtext/expressions/tests/ExpressionEvaluatorFunctionTest.xtend
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Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,7 @@ class ExpressionEvaluatorFunctionTest extends ExpressionEvaluatorTestBase {
tss = <string[]> [ "Hello", "Test!" ]
}
bool contains = contains(t.tss, "Hello")
bool notContains = contains(t.tis, "1")
bool notContains = contains(t.tis, 1)
''')
}

Expand Down
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