D vs nim

PR's welcome! Goal: up to date and objective comparison of features between D and nim, and 1:1 map of features to help D users learn nim and vice versa.

NOTE: tables render better (ie full width) with a chrome extension, see https://stackoverflow.com/a/49566642/1426932

NOTE: occasionally, nim code below will use the braces syntax skin to fit in 1 line

Help welcome, eg by filling in the entries with ? TODO and CHECKME, correcting wrong entries, or adding more (see also other files eg libraries.md).

See also libraries.md

features requested in latest D survey (https://rawgit.com/wilzbach/state-of-d/master/report.html) that are already supported in Nim

• From the D survey question "What language features do you miss?", these features are supported in Nim: tuples, named arguments, string interpolation, in-place struct initialization, UFCS for local symbols, writing files at compile-time
• these are doable in library code: assert diagnostics, static break
• these are sort of available: Static inheritance

compilation time

• https://forum.nim-lang.org/t/1372
• tcc instead of clang (but not on OSX, see https://github.com/wheineman/nrpl/issues/16)

runtime performance

See also https://github.com/timotheecour/D_vs_nim/issues/11

similar code comparison

differences (not clear if pro or con)

• nim has head immutability unlike D: http://nim-by-example.github.io/types/objects/
• Indentation based syntax, but supports syntax skins

map of corresponding features

See also libraries.md

links

• https://www.slant.co/versus/118/395/~d_vs_nim
• https://forum.nim-lang.org/t/1779 Nim vs D
• https://forum.dlang.org/post/[email protected] D vs nim
• http://gradha.github.io/articles/2015/02/goodbye-nim-and-good-luck.html
• https://www.quora.com/Of-the-emerging-systems-languages-Rust-D-Go-and-Nim-which-is-the-strongest-language-and-why
• https://github.com/kostya/benchmarks
• https://digitalmars.com/d/archives/digitalmars/D/D_and_Nim_251571.html
• https://forum.nim-lang.org/t/1983#12391 A few questions about Nim

nim questions (besides entries marked above with ?)

• does it have dfmt equivalent?

• instead of newSeq could we write new!Seq or new[Seq] or anything else that's generic and doesn't pollute namespace?

• how to use dirty templates/macros that require an import? eg:

template foo*() {.dirty.} { #[want: import os ]# let programName = getAppFilename() }

• how to compose arbitrary ranges/iterators in Nim?

• how to define a slice of type T from ptr + length? cf https://github.com/nim-lang/Nim/issues/5437 feature-request pointer size pair, (openArray as value) #5437

nim questions (answered)

• are there real immutable variables in nim ? A: https://www.reddit.com/r/nim/comments/2w32oi/immutability_in_nim/
• how to specify immutable inside for(foo in bar) ? A: immutability depends on iterator and by default iterators return immutable values.

var a = @[1, 2, 3, 4]
for item in a: item += 5  # compile-time error
for item in mitems(a):  item += 5  # ok

• how to search for symbols fooBar given that nim allows foobar fooBar foo_bar etc? A: nimgrep; also: Nim provides "nimsuggest" that can be used for vim, emacs, vscode, atom that autocompletes

• how to use global variables? (cf http://gradha.github.io/articles/2015/02/goodbye-nim-and-good-luck.html) A: Non-const global vars are not allowed in proc tagged noSideEffects and care must be used if accessed from multiple threads but there is nothing special about them otherwise.

• can we modify a slice of an immutable array declared by 'let'? A: Slicing doesn't return a var T for let arrays so you can't. Note that immutability for stack objects/array/types is deep but for ref/ptr types it is shallow, it means that the memory address pointed to cannot be modified but the content can.

• is there a robust way to write complex nim functions as a one liner (eg, for use in 1 line docs, in REPL etc); ideally by replacing indentation with braces A: (st1; st2; st3), or undocumented braces syntax skin:

#? braces

proc main() {
  echo "Hello"
}

when (isMainModule) {
  main()
}

no longer valid points

https://forum.nim-lang.org/t/1779/1#11314 => dmd backend license was changed recently