What general tips do you have for golfing in Nim? I'm looking for ideas which can be applied to code-golf problems and which are also at least somewhat specific to Nim (e.g. "remove comments" is not an answer).

Please post one tip per answer.


Flexible call syntax

Nim is pretty flexible when it comes to function call syntax. For example, here are some ways to call a function with one argument:

ord c

And ways to call a function with two arguments:

a.max b

Choose the golfiest version that works right for your situation, especially regarding precedence. For example, compare:

(abs n)+2

As opposed to:

abs n+2
  • 1
    \$\begingroup\$ Note that max a,b even works (sometimes). \$\endgroup\$
    – Copper
    Nov 26 '16 at 18:49

Use the future module

The future module contains two main byte-saving features: lambdas and list comprehensions. Lambdas are extremely useful.

For example, this:

proc f(s:any):any=s&", world!"

can be shortened to this:

import future
s=>s&", world!"

which saves a byte. Note, however, that lambdas can't be used outside of a parameter list -- so to test your code, you'll have to do something like this:

import future
proc test(f: string -> string) = echo f "Hello"
test(s=>s&", world!")

As well, list comprehensions can be used with the future module. For example, this code prints a seq (@[...]) of all squares less than 100 divisible by 4:

import future
echo lc[x*x|(x<-1..9,x*x mod 4==0),int]
  • \$\begingroup\$ For a fairer comparison it should be noted that you can sometimes use any instead of string (I'm assuming you chose the longest type name), but this still saves regardless. \$\endgroup\$
    – Sp3000
    Nov 26 '16 at 23:43
  • \$\begingroup\$ @Sp3000 I didn't know you could use any, thanks for the tip! You should post that as an answer. \$\endgroup\$
    – Copper
    Nov 27 '16 at 11:55
  • \$\begingroup\$ For an even better comparison, you can do proc(s:any):any=s&", world!", dropping the <space>f for an anonymous proc \$\endgroup\$
    – Sp3000
    Dec 20 '16 at 9:57

Unsigned operators

When working with nonnegative integers, sometimes it's better to use unsigned operators. Specifically, if possible, use /% and %% instead of div and mod.


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