Allow numbers to be written in queries in scientific (exponential) no…

…tation (#52)

language/cypher/src/main/java/com/albertoventurini/graphdbplugin/language/cypher/lexer/CypherLexer.flex

@@ -137,12 +137,20 @@ K_ON_EACH_TYPE={K_ON}{WHITE_SPACE}{_EACH}{WHITE_SPACE}{_TYPE}
 K_ON_TYPE={K_ON}{WHITE_SPACE}{_TYPE}
 K_IN_TRANSACTIONS={_IN}{WHITE_SPACE}{_TRANSACTIONS}
 
-L_IDENTIFIER=[a-zA-Z_][a-zA-Z_$0-9]*
+_DECIMAL_EXPONENT=[eE] [+-]? {_INTEGER_PART}+ {_PART_LETTER}*
+_INTEGER_PART= "_"? [0-9]
+
+L_IDENTIFIER={_LETTER}{_PART_LETTER}*
 L_IDENTIFIER_TEXT=\`[^`]+\`
-L_DECIMAL=(0|[1-9][0-9]*)\.[0-9]+
+L_DECIMAL=[0-9] {_INTEGER_PART}* "_"? "." {_INTEGER_PART}+ {_DECIMAL_EXPONENT}? {L_IDENTIFIER}?
+         | "." {_INTEGER_PART}+ {_DECIMAL_EXPONENT}? {L_IDENTIFIER}?
+         | [0-9] {_INTEGER_PART}* {_DECIMAL_EXPONENT} {L_IDENTIFIER}?
 L_INTEGER=0|[1-9][0-9]*
 L_STRING=('([^'\\]|\\.)*'|\"([^\"\\]|\\.)*\")
 
+_LETTER=[a-zA-Z]
+_PART_LETTER=[a-zA-Z_$0-9]
+
 LINE_COMMENT = "//" [^\r\n]*
 BLOCK_COMMENT = "/*" ( ([^"*"]|[\r\n])* ("*"+ [^"*""/"] )? )* ("*" | "*"+"/")?
 

testing/integration-neo4j/src/test/java/com/albertoventurini/graphdbplugin/test/integration/neo4j/tests/cypher/parsing/LexerTest.java

@@ -0,0 +1,15 @@
+package com.albertoventurini.graphdbplugin.test.integration.neo4j.tests.cypher.parsing;
+
+import com.albertoventurini.graphdbplugin.test.integration.neo4j.tests.cypher.util.BaseParsingTest;
+
+public class LexerTest extends BaseParsingTest {
+
+    public LexerTest() {
+        super("lexer");
+    }
+
+    public void testScientificNotation() {
+        doTest(true);
+    }
+
+}

testing/integration-neo4j/src/test/resources/parsing/lexer/ScientificNotation.cyp

@@ -0,0 +1,2 @@
+RETURN 1e6;
+RETURN 1.7976931348623157e+308;

testing/integration-neo4j/src/test/resources/parsing/lexer/ScientificNotation.txt

@@ -0,0 +1,41 @@
+Cypher file: FILE(0,43)
+  CypherStatementItemImpl(STATEMENT_ITEM)(0,11)
+    CypherStatementImpl(STATEMENT)(0,10)
+      CypherQueryOptionsImpl(QUERY_OPTIONS)(0,0)
+        <empty list>
+      CypherQueryImpl(QUERY)(0,10)
+        CypherRegularQueryImpl(REGULAR_QUERY)(0,10)
+          CypherSingleQueryImpl(SINGLE_QUERY)(0,10)
+            CypherSinglePartQueryImpl(SINGLE_PART_QUERY)(0,10)
+              CypherReadingWithReturnImpl(READING_WITH_RETURN)(0,10)
+                CypherReturnImpl(RETURN)(0,10)
+                  PsiElement(RETURN)('RETURN')(0,6)
+                  CypherReturnBodyImpl(RETURN_BODY)(7,10)
+                    CypherReturnItemsImpl(RETURN_ITEMS)(7,10)
+                      CypherReturnItemImpl(RETURN_ITEM)(7,10)
+                        CypherExpressionImpl(EXPRESSION)(7,10)
+                          CypherNumberLiteralImpl(NUMBER_LITERAL)(7,10)
+                            CypherDoubleLiteralImpl(DOUBLE_LITERAL)(7,10)
+                              CypherUnsignedDoubleImpl(UNSIGNED_DOUBLE)(7,10)
+                                PsiElement(decimal)('1e6')(7,10)
+    PsiElement(;)(';')(10,11)
+  CypherStatementItemImpl(STATEMENT_ITEM)(12,43)
+    CypherStatementImpl(STATEMENT)(12,42)
+      CypherQueryOptionsImpl(QUERY_OPTIONS)(12,12)
+        <empty list>
+      CypherQueryImpl(QUERY)(12,42)
+        CypherRegularQueryImpl(REGULAR_QUERY)(12,42)
+          CypherSingleQueryImpl(SINGLE_QUERY)(12,42)
+            CypherSinglePartQueryImpl(SINGLE_PART_QUERY)(12,42)
+              CypherReadingWithReturnImpl(READING_WITH_RETURN)(12,42)
+                CypherReturnImpl(RETURN)(12,42)
+                  PsiElement(RETURN)('RETURN')(12,18)
+                  CypherReturnBodyImpl(RETURN_BODY)(19,42)
+                    CypherReturnItemsImpl(RETURN_ITEMS)(19,42)
+                      CypherReturnItemImpl(RETURN_ITEM)(19,42)
+                        CypherExpressionImpl(EXPRESSION)(19,42)
+                          CypherNumberLiteralImpl(NUMBER_LITERAL)(19,42)
+                            CypherDoubleLiteralImpl(DOUBLE_LITERAL)(19,42)
+                              CypherUnsignedDoubleImpl(UNSIGNED_DOUBLE)(19,42)
+                                PsiElement(decimal)('1.7976931348623157e+308')(19,42)
+    PsiElement(;)(';')(42,43)