Functions valudation

Author: vepo

src/main/antlr4/dev/vepo/jsonata/functions/generated/JSONataGrammar.g4

@@ -36,7 +36,7 @@ expression:
     | BOOLEAN                                                                 # booleanValue    
     ;
 
-functionStatement: FV_NAME '(' parameterStatement (',' parameterStatement)*  ')' ;
+functionStatement: FV_NAME (('(' parameterStatement (',' parameterStatement)*  ')') | '()' ) ;
 parameterStatement: expression | functionDeclaration;
 functionDeclaration: 
     'function' '(' FV_NAME (',' FV_NAME)* ')' '{' expression+ '}' # functionDeclarationBuilder

src/main/java/dev/vepo/jsonata/functions/buildin/LengthJSONataFunction.java

@@ -10,7 +10,7 @@ public record LengthJSONataFunction(List<JSONataFunction> providers) implements
 
     public LengthJSONataFunction {
         if (providers.size() != 1) {
-            throw new IllegalArgumentException("$length function must have 1 argument");
+            throw new IllegalArgumentException("$length function must have 1 argument!");
         }
     }
 

src/main/java/dev/vepo/jsonata/functions/buildin/LowecaseJSONataFunction.java

@@ -9,7 +9,7 @@
 public record LowecaseJSONataFunction(List<JSONataFunction> providers) implements JSONataFunction {
     public LowecaseJSONataFunction {
         if (providers.size() != 1) {
-            throw new IllegalArgumentException("$lowecase function must have 1 argument!");
+            throw new IllegalArgumentException("$lowercase function must have 1 argument!");
         }
     }
 

src/main/java/dev/vepo/jsonata/functions/buildin/StringJSONataFunction.java

@@ -9,7 +9,7 @@
 public record StringJSONataFunction(List<JSONataFunction> providers) implements JSONataFunction {
     public StringJSONataFunction {
         if (providers.size() != 1) {
-            throw new IllegalArgumentException("$string function must have 1 argument");
+            throw new IllegalArgumentException("$string function must have 1 argument!");
         }
     }
 

src/main/java/dev/vepo/jsonata/functions/buildin/UppercaseJSONataFunction.java

@@ -9,7 +9,7 @@
 public record UppercaseJSONataFunction(List<JSONataFunction> providers) implements JSONataFunction {
     public UppercaseJSONataFunction {
         if (providers.size() != 1) {
-            throw new IllegalArgumentException("$uppercase function must have 1 argument");
+            throw new IllegalArgumentException("$uppercase function must have 1 argument!");
         }
     }
 

src/test/java/dev/vepo/jsonata/JSONataTest.java

@@ -261,6 +261,19 @@ void literalTest() {
 
     @Nested
     class Functions {
+        @Test
+        void argumentValidationTest() {
+            assertThatThrownBy(() -> jsonata("$string()")).isInstanceOf(IllegalArgumentException.class)
+                                                          .hasMessage("$string function must have 1 argument!");
+            assertThatThrownBy(() -> jsonata("$length()")).isInstanceOf(IllegalArgumentException.class)
+                                                          .hasMessage("$length function must have 1 argument!");
+            assertThatThrownBy(() -> jsonata("$lowercase()")).isInstanceOf(IllegalArgumentException.class)
+                                                             .hasMessage("$lowercase function must have 1 argument!");
+            assertThatThrownBy(() -> jsonata("$uppercase()")).isInstanceOf(IllegalArgumentException.class)
+                                                             .hasMessage("$uppercase function must have 1 argument!");
+
+        }
+
         @Test
         void stringTest() {
             assertThat(jsonata("$string(5)").evaluate("{}").asText()).isEqualTo("5");