xmake-nim

name	xmake-nim
description	Use when building Nim projects with xmake — binary/library targets with `.nim` sources, choosing the C backend (the default) vs C++, and mixing Nim with C.

Building Nim with Xmake

Nim compiles to C (or C++ / JavaScript) via nim c / nim cpp; xmake wraps this into a regular target model.

1. Minimal project

xmake create -l nim -t console hello
cd hello
xmake run

add_rules("mode.debug", "mode.release")

target("hello")
    set_kind("binary")
    add_files("src/*.nim")

2. Target kinds

target("app")       set_kind("binary")
target("mylib")     set_kind("static")
target("mydyn")     set_kind("shared")

3. Backend selection

target("app")
    add_files("src/main.nim")
    set_values("nim.backend", "c")         -- default
    -- or:
    set_values("nim.backend", "cpp")
    set_values("nim.backend", "objc")
    set_values("nim.backend", "js")

Most projects use c (native). cpp is required if you import C++ libraries via {.importcpp.}. js is for web targets.

4. Flags

target("app")
    add_files("src/*.nim")
    add_ncflags("-d:release", "--opt:speed")           -- Nim compiler flags
    add_cxflags("-O3")                                 -- passes to underlying C compiler

add_ncflags = Nim compiler flags. add_cxflags flows through to the C backend.

5. Toolchain

xmake f --toolchain=nim
xmake f --toolchain=nim --sdk=/opt/nim-2.0

6. Mixing Nim with C

Nim code can call C with {.importc.}; xmake can also compile C files alongside:

target("app")
    set_kind("binary")
    add_files("src/main.nim", "src/helper.c")
    add_includedirs("include")

Pitfalls

• Backend mismatch. If Nim code uses {.importcpp.}, the target must use nim.backend = "cpp". Otherwise link errors.
• nimble vs xmake. Nim's native package manager is nimble. Xmake doesn't integrate with it — declare Nim deps via nimble manually, and let xmake handle the build.
• -d:release passed as nim flag. It's a Nim define, not a C flag — must go in add_ncflags, not add_defines.

When to branch out

• Target basics → xmake-targets
• Mixing with C/C++ → xmake-targets