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Rw engine and Patterns for searching

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Gisela Decuzzi

Rw engine and Patterns for searching

Hello, I'm trying to understand how to define a correct pattern and I'm lost with the cases where I use a method pattern and the desired code is inside a block.

In the case where we search (methods) with metavariables and the code is inside a block.

An Example:

This pattern

`a: `aa `b: `bb

| `@temps |

``@.Stats.

``@.some size ``@.more.

``@.Stats2.

Does not match with:

insideABlock: arg1 part2: arg2

|temp1 temp3|

[arg1 size].

temp1 := arg2 + 3.

^arg2

After looking while I realize that is not matching with

part1: arg1 part2: arg2

|temp1 temp2 temp3|

arg1 size.

temp1 := arg2 + 3.

^arg2

Until I understand:

``@.some size ``@.more.

This should mean: anything that sends the message size, doesn't matter if we have something before or after, I think that this expression should match both cases.

But maybe I'm missunderstanding the patterns (again).

Any help with this will be really welcome!

camille teruel

Re: Rw engine and Patterns for searching

Hello Gisela,

On 21 août 2013, at 15:43, Gisela Decuzzi wrote:

Hello, I'm trying to understand how to define a correct pattern and I'm lost with the cases where I use a method pattern and the desired code is inside a block.
In the case where we search (methods) with metavariables and the code is inside a block.

An Example:

This pattern
`a: `aa `b: `bb
| `@temps |
``@.Stats.
``@.some size ``@.more.
``@.Stats2.

Putting a dot after the @ means that you want to match statements.

So '``@.some size' cannot match: 'arg1 size'.

Does not match with:
insideABlock: arg1 part2: arg2
|temp1 temp3|
[arg1 size].

temp1 := arg2 + 3.
^arg2

Then even if you remove the extra dots, the rule won't match the method you give.

This is because this method has no statements matching '``@some size' (even if it has a block that has a statement that can).

So here is a rule that can match your method:

`a: `aa `b: `bb
| `@temps |
`@.stms1.

[ `@rcv size ].

`@.stms2.

After looking while I realize that is not matching with

part1: arg1 part2: arg2
|temp1 temp2 temp3|
arg1 size.
temp1 := arg2 + 3.

^arg2

This one however can be matched by your rule (without the extra dots).

I think that you should try to parse expressions instead of full methods (RBParseTreeSearcher>>#matches:do: instead of RBParseTreeSearcher>>#matchesMethod:do:).

You could just try to match '`@rcv size': it would succeed in both methods.

Until I understand:
``@.some size ``@.more.
This should mean: anything that sends the message size, doesn't matter if we have something before or after, I think that this expression should match both cases.

But maybe I'm missunderstanding the patterns (again).

It should work like that (modulo bugs)

` denotes a metavariable
adding @ means you're looking for a list of elements

ex: `receiver `@msg: `@arg matches every message

adding a . means you're looking for a statement (or a list of statement if you combine it with @)
adding # means you're looking for a literal
adding another ` means that the pattern will be searched recursively in each subexpressions even if the top one already matched

it sometimes leads to infinite loops, but I don't remember exactly when
ex: in 'foo bar bar' :

if you search for '`rcv bar' you'll find one match ('foo bar bar')
if you search for '``rcv bar' you'll find two matches ('foo bar' and 'foo bar bar').

and I think it's all

Any help with this will be really welcome!

Gisela Decuzzi

Re: Rw engine and Patterns for searching

Hi Camille!

Thanks for the details about using the dot.

I know that for this case is better matching an expression but it sounded strange at the begining the behavior inside the block despite of the ``@

I will take a look in the matching. Because like that we cannot say that we don't care if we have that piece of code and we should repeat the pattern with an or containing the block and without it.

But I don't understand if the actual behavior is really a bug or it's a feature...

2013/8/21 Camille Teruel <[hidden email]>

Hello Gisela,

On 21 août 2013, at 15:43, Gisela Decuzzi wrote:

Hello, I'm trying to understand how to define a correct pattern and I'm lost with the cases where I use a method pattern and the desired code is inside a block.

In the case where we search (methods) with metavariables and the code is inside a block.

An Example:

This pattern
`a: `aa `b: `bb
| `@temps |
``@.Stats.
``@.some size ``@.more.
``@.Stats2.

Putting a dot after the @ means that you want to match statements.
So '``@.some size' cannot match: 'arg1 size'.

Does not match with:
insideABlock: arg1 part2: arg2
|temp1 temp3|
[arg1 size].

temp1 := arg2 + 3.
^arg2

Then even if you remove the extra dots, the rule won't match the method you give.

This is because this method has no statements matching '``@some size' (even if it has a block that has a statement that can).
So here is a rule that can match your method:
`a: `aa `b: `bb
| `@temps |
`@.stms1.
[ `@rcv size ].
`@.stms2.

After looking while I realize that is not matching with

part1: arg1 part2: arg2
|temp1 temp2 temp3|
arg1 size.
temp1 := arg2 + 3.

^arg2

This one however can be matched by your rule (without the extra dots).
I think that you should try to parse expressions instead of full methods (RBParseTreeSearcher>>#matches:do: instead of RBParseTreeSearcher>>#matchesMethod:do:).

You could just try to match '`@rcv size': it would succeed in both methods.

Until I understand:
``@.some size ``@.more.

This should mean: anything that sends the message size, doesn't matter if we have something before or after, I think that this expression should match both cases.

But maybe I'm missunderstanding the patterns (again).

It should work like that (modulo bugs)
` denotes a metavariable
adding @ means you're looking for a list of elements

ex: `receiver `@msg: `@arg matches every message
adding a . means you're looking for a statement (or a list of statement if you combine it with @)
adding # means you're looking for a literal

adding another ` means that the pattern will be searched recursively in each subexpressions even if the top one already matched
it sometimes leads to infinite loops, but I don't remember exactly when

ex: in 'foo bar bar' :
if you search for '`rcv bar' you'll find one match ('foo bar bar')
if you search for '``rcv bar' you'll find two matches ('foo bar' and 'foo bar bar').

and I think it's all

Any help with this will be really welcome!

camille teruel

Re: Rw engine and Patterns for searching

On 23 août 2013, at 05:16, Gisela Decuzzi wrote:

Hi Camille!
Thanks for the details about using the dot.
I know that for this case is better matching an expression but it sounded strange at the begining the behavior inside the block despite of the ``@

As far as I understand, there is no difference between ` and `` when you try to match a method because there is no such thing as a submethod.

No matter where you recurse in a method, you'll never find another method that can potentially match.

I will take a look in the matching.

Good luck.

Stef suggested to see in visualworks if there is a new version.

Because like that we cannot say that we don't care if we have that piece of code and we should repeat the pattern with an or containing the block and without it.

What you can do is still to try matching an expression but with an additional condition.

By the way I forgot to mention the `{ :node | "some smalltalk code here" } syntax in my last mail: it permits to match only the nodes that satisfy the "wrapped block".

But I don't understand if the actual behavior is really a bug or it's a feature...

Its more a limitation.

2013/8/21 Camille Teruel <[hidden email]>

Hello Gisela,

On 21 août 2013, at 15:43, Gisela Decuzzi wrote:

Hello, I'm trying to understand how to define a correct pattern and I'm lost with the cases where I use a method pattern and the desired code is inside a block.

In the case where we search (methods) with metavariables and the code is inside a block.

An Example:

This pattern
`a: `aa `b: `bb
| `@temps |
``@.Stats.
``@.some size ``@.more.
``@.Stats2.

Putting a dot after the @ means that you want to match statements.
So '``@.some size' cannot match: 'arg1 size'.

Does not match with:
insideABlock: arg1 part2: arg2
|temp1 temp3|
[arg1 size].

temp1 := arg2 + 3.
^arg2

Then even if you remove the extra dots, the rule won't match the method you give.

This is because this method has no statements matching '``@some size' (even if it has a block that has a statement that can).
So here is a rule that can match your method:
`a: `aa `b: `bb
| `@temps |
`@.stms1.
[ `@rcv size ].
`@.stms2.

After looking while I realize that is not matching with

part1: arg1 part2: arg2
|temp1 temp2 temp3|
arg1 size.
temp1 := arg2 + 3.

^arg2

This one however can be matched by your rule (without the extra dots).
I think that you should try to parse expressions instead of full methods (RBParseTreeSearcher>>#matches:do: instead of RBParseTreeSearcher>>#matchesMethod:do:).

You could just try to match '`@rcv size': it would succeed in both methods.

Until I understand:
``@.some size ``@.more.

This should mean: anything that sends the message size, doesn't matter if we have something before or after, I think that this expression should match both cases.

But maybe I'm missunderstanding the patterns (again).

It should work like that (modulo bugs)
` denotes a metavariable
adding @ means you're looking for a list of elements

ex: `receiver `@msg: `@arg matches every message
adding a . means you're looking for a statement (or a list of statement if you combine it with @)
adding # means you're looking for a literal

adding another ` means that the pattern will be searched recursively in each subexpressions even if the top one already matched
it sometimes leads to infinite loops, but I don't remember exactly when

ex: in 'foo bar bar' :
if you search for '`rcv bar' you'll find one match ('foo bar bar')
if you search for '``rcv bar' you'll find two matches ('foo bar' and 'foo bar bar').

and I think it's all

Any help with this will be really welcome!