improve "if" function. fix #53

Author: Horcrux7

src/com/inet/lib/less/LessParser.java

@@ -1132,6 +1132,10 @@ private Expression concat( Expression left, char operator, Expression right ) {
         Operation op;
         if( left.getClass() == Operation.class && ((Operation)left).getOperator() == operator ) {
             op = (Operation)left;
+        } else if( right != null && right.getClass() == Operation.class && ((Operation)right).getOperator() == operator ) {
+            op = (Operation)right;
+            op.addLeftOperand( left );
+            return op;
         } else {
             op = new Operation( reader, left, operator );
         }

src/com/inet/lib/less/Operation.java

@@ -1,7 +1,7 @@
 /**
  * MIT License (MIT)
  *
- * Copyright (c) 2014 - 2016 Volker Berlin
+ * Copyright (c) 2014 - 2019 Volker Berlin
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -433,6 +433,23 @@ public boolean booleanValue(CssFormatter formatter) {
                 return value;
             case '!':
                 return !leftOp.booleanValue( formatter );
+            case ' ':
+                if( leftOp instanceof ValueExpression && "not".equals( leftOp.toString() ) ) {
+                    return !operands.get( 1 ).booleanValue( formatter );
+                }
+                if( operands.size() == 3 ) {
+                    Expression op = operands.get( 1 );
+                    if( op instanceof ValueExpression ) {
+                        Expression rightOp = operands.get( 2 );
+                        switch( op.toString() ) {
+                            case "and":
+                                return leftOp.booleanValue( formatter ) & rightOp.booleanValue( formatter );
+                            case "or":
+                                return leftOp.booleanValue( formatter ) | rightOp.booleanValue( formatter );
+                        }
+                    }
+                }
+                break;
             case '>':
             case '<':
             case '=':

src/com/inet/lib/less/ValueExpression.java

@@ -260,32 +260,41 @@ private void eval( CssFormatter formatter ) {
                 str = str.toLowerCase();
                 rgb = getRgbFromColorConst( str );
                 if( rgb == -1 ) {
-                    if( str.equals( "transparent" ) ) {
-                        value = 0;
-                        type = RGBA;
-                        return;
-                    } else {
-                        ParsePosition pos = new ParsePosition( 0 );
-                        Number number = formatter.getFormat().parse( str, pos );
-                        if( number == null ) {
-                            if( str.startsWith( "+" ) ) { // DecimalFormat can not parse an option plus sign
-                                pos.setIndex( 1 );
-                                number = formatter.getFormat().parse( str, pos );
-                                if( number == null ) {
+                    switch( str ) {
+                        case "transparent":
+                            value = 0;
+                            type = RGBA;
+                            return;
+                        case "true":
+                            type = BOOLEAN;
+                            value = -1;
+                            return;
+                        case "false":
+                            type = BOOLEAN;
+                            value = 0;
+                            return;
+                        default:
+                            ParsePosition pos = new ParsePosition( 0 );
+                            Number number = formatter.getFormat().parse( str, pos );
+                            if( number == null ) {
+                                if( str.startsWith( "+" ) ) { // DecimalFormat can not parse an option plus sign
+                                    pos.setIndex( 1 );
+                                    number = formatter.getFormat().parse( str, pos );
+                                    if( number == null ) {
+                                        type = STRING;
+                                        return;
+                                    }
+                                } else {
                                     type = STRING;
                                     return;
                                 }
-                            } else {
-                                type = STRING;
-                                return;
                             }
-                        }
-                        value = number.doubleValue();
-                        if( pos.getIndex() != str.length() ) {
-                            unit = str.substring( pos.getIndex() );
-                        }
-                        type = NUMBER;
-                        return;
+                            value = number.doubleValue();
+                            if( pos.getIndex() != str.length() ) {
+                                unit = str.substring( pos.getIndex() );
+                            }
+                            type = NUMBER;
+                            return;
                     }
                 }
             }

test/com/inet/lib/less/samples/less_org_doc/logical/if2.css

@@ -0,0 +1,7 @@
+.if {
+  a: bar;
+  b: foo;
+  c: foo;
+  d: blue;
+  e: blue;
+}

test/com/inet/lib/less/samples/less_org_doc/logical/if2.less

@@ -0,0 +1,7 @@
+.if {
+  a: if(not (true), foo, bar);
+  b: if((true) and (2 > 1), foo, bar);
+  c: if((false) or (isstring("boo!")), foo, bar);
+  d: if(2 > 1, blue, green);
+  e: if((2 > 1), blue, green);
+}