How to program faster, (generate code from a pattern?) - ruby

Question

I frequently run into problems that could be solved with automating code writing, but aren't long enough to justify it as tediously entering each piece is faster.
Here is an example:
Putting lists into dictionaries and things like this. Converting A into B.
A
hotdog HD
hamburger HB
hat H
B
def symbolizeType
case self.type
when "hotdog"
return "HD"
when "hamburger"
return "HB"
when "hat"
return "H"
end
Sure I could come up with something to do this automatically, but it would only make sense if the list was 100+ items long. For a list of 10-20 items, is there a better solution than tediously typing? This is a Ruby example, but I typically run into cases like this all the time. Instead of a case statement, maybe it's a dictionary, maybe it's a list, etc.
My current solution is a python template with the streaming input and output already in place, and I just have to write the parsing and output code. This is pretty good, but is there better? I feel like this would be something VIM macro would excel at, but I'm that experienced with VIM. Can VIM do this easily?

Answer 1

For vim, it'd be a macro running over a list of space separated pairs of words, inserting the first 'when "' bit, the long form word 'hotdog', the ending quote, a newline and 'return "', and then the abbreviation and then final quote, then going back to the list and repeating.
Starting with a register w of:
when "
register r of:
return "
an initial list of:
hotdog HD
hamburger HB
hat H
and a starting file of:
def symbolizeType
case self.type
"newline here"
you can use the following macro at the start of the initial list:
^"ayeeeb"byeo"wp"apa"^Mrb"j
where ^M is a newline.

Answer 2

I do this frequently, and I use a single register and a macro, so I'll share.
Simply pick a register, record your keystrokes, and then replay your keystrokes from the register.
This is a long explanation, but the process is extremely simple and intuitive.
Here are the steps that I would take:
A. The starting text
hotdog HD
hamburger HB
hat H
B. Insert the initial, non-repetitive lines preceding the text to transform
def symbolizeType
case self.type
hotdog HD
hamburger HB
hat H
C. Transform the first line, while recording your keystrokes in a macro
This step I'll write out in detailed sub-steps.
Place the cursor on the first line to transform ("hotdog") and type qa to begin recording your keystrokes as a macro into register a.
Type ^ to move the cursor to the start of the line
Type like you normally would to transform the line to what you want, which for me comes out looking like the following macro
^i^Iwhen "^[ea"^[ldwi^M^Ireturn "^[ea"^[j
Where ^I is Tab, ^[ is Esc, and ^M is Enter.
After the line is transformed to your liking, move your cursor to the next line that you want to transform. You can see this in the macro above with the final j at the end.
This will allow you to automatically repeat the macro while it cycles through each repetitive line.
Stop recording the macro by typing q again.
You can then replay the macro from register a as many times as you like using a standard vim count prefix, in this case two consecutive times starting from the next line to transform.
2#a
This gives the following text
def symbolizeType
case self.type
when "hotdog"
return "HD"
when "hamburger"
return "HB"
when "hat"
return "H"
D. Finally, insert the ending non-repetitive text
def symbolizeType
case self.type
when "hotdog"
return "HD"
when "hamburger"
return "HB"
when "hat"
return "H"
end
Final Comments
This works very quick for any random, repetitive text, and I find it very fluent.
Simply pick a register, record your keystrokes, and then replay your keystrokes from the register.

Answer 3

For things like this I have a few ways of making it easier. One is to use an editor like Sublime Text that allows you to multi-edit a number of things at once, so you can throw in markup with a few keystrokes and convert that into a Hash like:
NAME_TO_CODE = {
hotdog: 'HD',
hamburger: 'HB',
hat: 'H'
}
Not really a whole lot changed there. Your function looks like:
def symbolize_type(type)
NAME_TO_CODE[type.to_sym]
end
Defining this as a data structure has the bonus of being able to manipulate it:
CODE_TO_NAME = NAME_TO_CODE.invert
Now you can do this:
def unsymbolize_type(symbol)
CODE_TO_NAME[symbol.to_s]
end
You can also get super lazy and just parse it on the fly:
NAME_TO_CODE = Hash[%w[
hotdog HD
hamburger HB
hat H
].each_slice(2).to_a]

Answer 4

snippets are like the built-in :abbreviate on steroids, usually with parameter insertions, mirroring, and multiple stops inside them. One of the first, very famous (and still widely used) Vim plugins is snipMate (inspired by the TextMate editor); unfortunately, it's not maintained any more; though there is a fork. A modern alternative (that requires Python though) is UltiSnips. There are more, see this list on the Vim Tips Wiki.
There are three things to evaluate: First, the features of the snippet engine itself, second, the quality and breadth of snippets provided by the author or others; third, how easy it is to add new snippets.