Method names and alias

Ruby
1

Hello all,

In Unix, you can create a symlink to an executable, and have the program
behave differently depending on how it was called by testing argv[0]. I
would
like to do something similar with Ruby methods using alias.

I have many methods which come in pairs, a version each for signed and
unsigned numbers. These methods differ by only one line, eg:

def load_byte(destination, base_address, offset)
<snip 15 lines>
@registers.gen[destination] = bitstring_to_int(byte)
true
end

def load_byte_unsigned(destination, base_address, offset)
<snip 15 lines>
@registers.gen[destination] = bitstring_to_int(byte, signed=false)
true
end

My code would be considerably DRYer if I could make ‘load_byte_unsigned’
an
alias to ‘load_byte’, and have the method inspect the name it was called
as
to decide if it should run ‘bitstring_to_int(byte, signed=false)’ or
not.

Is there a way to do this?

If not, I suppose my best bet is to move the snipped 15 lines to
a ‘load_byte_common’ method and make ‘load_byte’ and
‘load_byte_unsigned’
thin wrappers around it?

Thanks for consideration,
-d

2

On 9/1/07, darren kirby [email protected] wrote:

<snip 15 lines>
My code would be considerably DRYer if I could make ‘load_byte_unsigned’ an
alias to ‘load_byte’, and have the method inspect the name it was called as
z> to decide if it should run ‘bitstring_to_int(byte, signed=false)’ or
not.

Well this is your problem, “have the method inspect the name it was
called as”. I guess if you really want to DRY them up ( although the
other approach you suggested sounds good enough), you can use
method_missing and capture method names and do stuff based on that.

Also, if there is a way to determine method that you intend to call
based on argument data type, then you can inspect your arguments and
do DRY stuff. But i guess you would have already thought out that
possibility. Anyways…

darren kirby :: Part of the problem since 1976 :: http://badcomputer.org
“…the number of UNIX installations has grown to 10, with more expected…”

  • Dennis Ritchie and Ken Thompson, June 1972

–
Let them talk of their oriental summer climes of everlasting
conservatories; give me the privilege of making my own summer with my
own coals.

http://blog.gnufied.org

3

On Aug 31, 1:47 pm, darren kirby [email protected] wrote:

My code would be considerably DRYer if I could make ‘load_byte_unsigned’ an
alias to ‘load_byte’, and have the method inspect the name it was called as
to decide if it should run ‘bitstring_to_int(byte, signed=false)’ or not.

Is there a way to do this?

I can’t offer you a way to do this, but:

If not, I suppose my best bet is to move the snipped 15 lines to
a ‘load_byte_common’ method and make ‘load_byte’ and ‘load_byte_unsigned’
thin wrappers around it?

I’d personally do something like:

def load_byte( byte, unsigned=false )
#…your code here…
end

def load_byte_unsigned( byte )
load_byte( byte, true )
end

A (private?) utility function is certainly possible, but not the way
I’d go, or needed.

4

From: darren kirby [mailto:[email protected]]

def load_byte(destination, base_address, offset)

<snip 15 lines>

@registers.gen[destination] = bitstring_to_int(byte)

true

end

def load_byte_unsigned(destination, base_address, offset)

<snip 15 lines>

@registers.gen[destination] = bitstring_to_int(byte, signed=false)

true

end

def load_byte(destination, base_address, offset, signed=true)
<snip 15 lines>
@registers.gen[destination] = bitstring_to_int(byte,signed)
true
end

load_byte(destination, base_address, offset) #signed
load_byte(destination, base_address, offset, signed=false) #unsigned

5

quoth the Phrogz:

a ‘load_byte_common’ method and make ‘load_byte’ and ‘load_byte_unsigned’
end
Thanks Phrogz,

This gives me some ideas on how to clean up the code a bit.

@Hemant:

I guess I was hoping there may have been some "if self.name ==
“load_byte”
magic that I could have used.

@Pena:

Thanks, but I cannot change the name of the method, that is, there must
be an
unsigned counterpart, as I am writing methods which emulate Mips32 ISA
and I
want my methods to match the ops…the real methos names are 'lb, and
‘lbu’
so…

-d