Decouple ANTLR AST from Painless

buildSrc/src/main/resources/checkstyle_suppressions.xml

@@ -7,8 +7,8 @@
   <!-- On Windows, Checkstyle matches files using \ path separator -->
 
   <!-- These files are generated by ANTLR so its silly to hold them to our rules. -->
-  <suppress files="org[/\\]elasticsearch[/\\]painless[/\\]PainlessLexer\.java" checks="." />
-  <suppress files="org[/\\]elasticsearch[/\\]painless[/\\]PainlessParser(|BaseVisitor|Visitor)\.java" checks="." />
+  <suppress files="org[/\\]elasticsearch[/\\]painless[/\\]antlr[/\\]PainlessLexer\.java" checks="." />
+  <suppress files="org[/\\]elasticsearch[/\\]painless[/\\]antlr[/\\]PainlessParser(|BaseVisitor|Visitor)\.java" checks="." />
 
   <!-- Hopefully temporary suppression of LineLength on files that don't pass it. We should remove these when we the
     files start to pass. -->

modules/lang-painless/ant.xml

@@ -49,7 +49,7 @@
         <include name="@{grammar}ParserVisitor.java" />
         <include name="@{grammar}ParserBaseVisitor.java" />
       </patternset>
-      <property name="output.path" location="src/main/java/org/elasticsearch/painless"/>
+      <property name="output.path" location="src/main/java/org/elasticsearch/painless/antlr"/>
       <!-- delete parser and lexer so files will be generated -->
       <delete dir="${output.path}">
         <patternset refid="grammar.@{grammar}.patternset"/>
@@ -63,15 +63,15 @@
       <local name="grammar.path"/>
       <local name="output.path"/>
       <property name="grammar.path" location="src/main/antlr"/>
-      <property name="output.path" location="src/main/java/org/elasticsearch/painless"/>
+      <property name="output.path" location="src/main/java/org/elasticsearch/painless/antlr"/>
       <!-- invoke ANTLR4 -->
       <java classname="org.antlr.v4.Tool" fork="true" failonerror="true" classpathref="regenerate.classpath" taskname="antlr">
         <sysproperty key="file.encoding" value="UTF-8"/>
         <sysproperty key="user.language" value="en"/>
         <sysproperty key="user.country" value="US"/>
         <sysproperty key="user.variant" value=""/>
         <arg value="-package"/>
-        <arg value="org.elasticsearch.painless"/>
+        <arg value="org.elasticsearch.painless.antlr"/>
         <arg value="-o"/>
         <arg path="${output.path}"/>
         <arg path="${grammar.path}/@{grammar}Lexer.g4"/>
@@ -85,15 +85,15 @@
       <local name="grammar.path"/>
       <local name="output.path"/>
       <property name="grammar.path" location="src/main/antlr"/>
-      <property name="output.path" location="src/main/java/org/elasticsearch/painless"/>
+      <property name="output.path" location="src/main/java/org/elasticsearch/painless/antlr"/>
       <!-- invoke ANTLR4 -->
       <java classname="org.antlr.v4.Tool" fork="true" failonerror="true" classpathref="regenerate.classpath" taskname="antlr">
         <sysproperty key="file.encoding" value="UTF-8"/>
         <sysproperty key="user.language" value="en"/>
         <sysproperty key="user.country" value="US"/>
         <sysproperty key="user.variant" value=""/>
         <arg value="-package"/>
-        <arg value="org.elasticsearch.painless"/>
+        <arg value="org.elasticsearch.painless.antlr"/>
         <arg value="-no-listener"/>
         <arg value="-visitor"/>
         <!-- <arg value="-Xlog"/> -->
@@ -110,7 +110,7 @@
       <local name="grammar.path"/>
       <local name="output.path"/>
       <property name="grammar.path" location="src/main/antlr"/>
-      <property name="output.path" location="src/main/java/org/elasticsearch/painless"/>
+      <property name="output.path" location="src/main/java/org/elasticsearch/painless/antlr"/>
       <patternset id="grammar.@{grammar}.patternset">
         <include name="@{grammar}Lexer.java" />
         <include name="@{grammar}Parser.java" />

modules/lang-painless/src/main/antlr/PainlessLexer.g4

@@ -63,7 +63,7 @@ EQR:     '===';
 NE:      '!=';
 NER:     '!==';
 BWAND:   '&';
-BWXOR:   '^';
+XOR:     '^';
 BWOR:    '|';
 BOOLAND: '&&';
 BOOLOR:  '||';

modules/lang-painless/src/main/antlr/PainlessParser.g4

@@ -92,9 +92,9 @@ expression
     |               TRUE                                                # true
     |               FALSE                                               # false
     |               NULL                                                # null
-    | <assoc=right> extstart increment                                  # postinc
-    | <assoc=right> increment extstart                                  # preinc
-    |               extstart                                            # external
+    | <assoc=right> chain ( INCR | DECR )                               # postinc
+    | <assoc=right> ( INCR | DECR ) chain                               # preinc
+    |               chain                                               # read
     | <assoc=right> ( BOOLNOT | BWNOT | ADD | SUB ) expression          # unary
     | <assoc=right> LP decltype RP expression                           # cast
     |               expression ( MUL | DIV | REM ) expression           # binary
@@ -103,39 +103,35 @@ expression
     |               expression ( LT | LTE | GT | GTE ) expression       # comp
     |               expression ( EQ | EQR | NE | NER ) expression       # comp
     |               expression BWAND expression                         # binary
-    |               expression BWXOR expression                         # binary
+    |               expression XOR expression                           # binary
     |               expression BWOR expression                          # binary
     |               expression BOOLAND expression                       # bool
     |               expression BOOLOR expression                        # bool
     | <assoc=right> expression COND expression COLON expression         # conditional
-    | <assoc=right> extstart ( ASSIGN | AADD | ASUB | AMUL | ADIV
+    | <assoc=right> chain ( ASSIGN | AADD | ASUB | AMUL | ADIV
                                       | AREM | AAND | AXOR | AOR
                                       | ALSH | ARSH | AUSH ) expression # assignment
     ;
 
-extstart
-    : extprec
-    | extcast
-    | extvar
-    | extnew
-    | extstring
+chain
+    : linkprec
+    | linkcast
+    | linkvar
+    | linknew
+    | linkstring
     ;
 
-extprec:   LP ( extprec | extcast | extvar | extnew | extstring ) RP ( extdot | extbrace )?;
-extcast:   LP decltype RP ( extprec | extcast | extvar | extnew | extstring );
-extbrace:  LBRACE expression RBRACE ( extdot | extbrace )?;
-extdot:    DOT ( extcall | extfield );
-extcall:   EXTID arguments ( extdot | extbrace )?;
-extvar:    identifier ( extdot | extbrace )?;
-extfield:  ( EXTID | EXTINTEGER ) ( extdot | extbrace )?;
-extnew:    NEW identifier ( ( arguments extdot? ) | ( ( LBRACE expression RBRACE )+ extdot? ) );
-extstring: STRING (extdot | extbrace )?;
+linkprec:   LP ( linkprec | linkcast | linkvar | linknew | linkstring ) RP ( linkdot | linkbrace )?;
+linkcast:   LP decltype RP ( linkprec | linkcast | linkvar | linknew | linkstring );
+linkbrace:  LBRACE expression RBRACE ( linkdot | linkbrace )?;
+linkdot:    DOT ( linkcall | linkfield );
+linkcall:   EXTID arguments ( linkdot | linkbrace )?;
+linkvar:    identifier ( linkdot | linkbrace )?;
+linkfield:  ( EXTID | EXTINTEGER ) ( linkdot | linkbrace )?;
+linknew:    NEW identifier ( ( arguments linkdot? ) | ( ( LBRACE expression RBRACE )+ linkdot? ) );
+linkstring: STRING (linkdot | linkbrace )?;
 
 arguments
     : ( LP ( expression ( COMMA expression )* )? RP )
     ;
 
-increment
-    : INCR
-    | DECR
-    ;