j2py fails to convert

[pmav99]

Hi I tried to use java2python on this library and it fails to do the convertion for some of the files.

For example, <src/model/Dof.java> and <src/model/FeLoadData.java> are converted without problems, but <src/model/FeModelData.java> fails with the following traceback.

I'm on Linux 64bit. and I have Installed j2py 0.5.1.

any ideas?

P.

Traceback (most recent call last):
  File "/usr/bin/j2py", line 259, in <module>
    sys.exit(runMain(configScript(sys.argv[1:])))
  File "/usr/bin/j2py", line 57, in runMain
    return runOneOrMany(options)
  File "/usr/bin/j2py", line 83, in runOneOrMany
    return runTransform(options)
  File "/usr/bin/j2py", line 135, in runTransform
    module.walk(tree)
  File "/usr/lib/python2.7/site-packages/java2python/compiler/visitor.py", line 86, in walk
    visitor.walk(child, memo)
  File "/usr/lib/python2.7/site-packages/java2python/compiler/visitor.py", line 86, in walk
    visitor.walk(child, memo)
  File "/usr/lib/python2.7/site-packages/java2python/compiler/visitor.py", line 86, in walk
    visitor.walk(child, memo)
  File "/usr/lib/python2.7/site-packages/java2python/compiler/visitor.py", line 86, in walk
    visitor.walk(child, memo)
  File "/usr/lib/python2.7/site-packages/java2python/compiler/visitor.py", line 86, in walk
    visitor.walk(child, memo)
  File "/usr/lib/python2.7/site-packages/java2python/compiler/visitor.py", line 83, in walk
    visitor = self.accept(tree, memo)
  File "/usr/lib/python2.7/site-packages/java2python/compiler/visitor.py", line 43, in accept
    return call(node, memo)
  File "/usr/lib/python2.7/site-packages/java2python/compiler/visitor.py", line 443, in acceptFor
    if not node.firstChildOfType(tokens.BLOCK_SCOPE).children:
AttributeError: 'NoneType' object has no attribute 'children'

[iuliux]

I reduced the example to the following:

public class FeModelData {
    public void setNodeCoords() {
        for (int i = 0; i < 3; i++) i = 0;
    }
}

From here results that a for statement without brackets can not be handled.

The Java AST looks like this:

FOR for [line=3, start=32, stop=60]
    FOR_INIT [start=35, stop=41]
        VAR_DECLARATION [start=35, stop=41]
            LOCAL_MODIFIER_LIST [start=35, stop=34]
            TYPE [start=35]
                INT int [line=3, start=35]
            VAR_DECLARATOR_LIST [start=37, stop=41]
                VAR_DECLARATOR [start=37, stop=41]
                    IDENT i [line=3, start=37]
                    EXPR [start=41]
                        DECIMAL_LITERAL 0 [line=3, start=41]
    FOR_CONDITION [start=44, stop=48]
        EXPR [start=44, stop=48]
            LESS_THAN < [line=3, start=44, stop=48]
                IDENT i [line=3, start=44]
                DECIMAL_LITERAL 3 [line=3, start=48]
    FOR_UPDATE [start=51, stop=52]
        EXPR [start=51, stop=52]
            POST_INC [line=3, start=51, stop=52]
                IDENT i [line=3, start=51]
    EXPR [start=55, stop=60]
        ASSIGN = [line=3, start=55, stop=59]
            IDENT i [line=3, start=55]
            DECIMAL_LITERAL 0 [line=3, start=59]

There is no BLOCK_SCOPE and one is expected.

[gul2u]

I was having a similar issue when attempting to utilize j2py.

Ensuring all conditionals and loops are defined with curly braces resolves the issue.

Thanks for the tip @iuliux

[stuaxo]

It looks like for(..) and if ( ..) blocks without brackets need to generate a BLOCKSCOPE..

@natural have any idea where someone would need to start to

i add failing tests for this ii implement ?

[stuaxo]

@gul2u @iuliux - I guess using a java formatter/beautifier on the code base as a preprocessing step might work while the bug exists.

[stuaxo]

Have worked out how to make the simple example -

for(int i = 0; i < 3; i++) System.out.println("Hello world");

Not crash ... though not how to output the SOPL yet ..

[stuaxo]

Tried this - no crash - but not sure how to output the actual statement in the for loop:

diff --git a/home/stuaxo/.virtualenvs/tmp/lib/python2.7/site-packages/java2python/compiler/visitor.py b/java2python/compiler/visitor.py
index cdac7d0..4109883 100644
--- a/home/stuaxo/.virtualenvs/tmp/lib/python2.7/site-packages/java2python/compiler/visitor.py
+++ b/java2python/compiler/visitor.py
@@ -440,13 +440,10 @@ class MethodContent(Base):
         else:
             whileStat.expr.walk(cond, memo)
         whileBlock = self.factory.methodContent(parent=self)
-        if node.children[3].type == tokens.EXPR:
-             whileBlock.walk(node.firstChildOfType(tokens.BLOCK_SCOPE), memo)
+        if not node.firstChildOfType(tokens.BLOCK_SCOPE).children:
+            self.factory.expr(left='pass', parent=whileBlock)
         else:
-            if not node.firstChildOfType(tokens.BLOCK_SCOPE).children:
-                self.factory.expr(left='pass', parent=whileBlock)
-            else:
-                whileBlock.walk(node.firstChildOfType(tokens.BLOCK_SCOPE), memo)
+            whileBlock.walk(node.firstChildOfType(tokens.BLOCK_SCOPE), memo)
         updateStat = self.factory.expr(parent=whileBlock)
         updateStat.walk(node.firstChildOfType(tokens.FOR_UPDATE), memo)

[colinoflynn]

I ran into this also - as a workaround as suggested I used a code beautifier. I used this one in particular: http://www.tiobe.com/index.php/content/products/jacobe/Jacobe.html

You can run as follows for example, this worked for me, note it will overwrite the existing files so keep a copy of them (it also saves them with a new extension in that same directory):

jacobe -cfg=sun.cng -overwrite ../dirtofiles/*.java

[zhouyang430]

Hi did you solve the problem? I have used java formatter and having all {} for loops still don't work. HELP!