Simple build pipeline...

build.txt

// Glob up C++ sources
var srcs = combine([
  glob("src/*{.h,.cpp}")
])

// Exclude some sources
srcs = exclude(srcs, [glob("test/**")])

// Grab all the object files, creates multiple targets
var objects = compile_cpp(srcs).outputs

// Next, add a linking step that creates libfoo.a
var linkStep = link_cpp("foo", objects)

// We can make it a shared library
linkStep.shared = true

custom.txt

macro compile_wat_to_wasm(source) {
  var name = extension(source, ".wasm")
  return process(["wat2wasm", "-o", name, source])
}

// Globs many sources through wat2wasm
macro compile_wasm(sources) {
  return multi_target(sources, compile_wat_to_wasm)
}

// Call it. Produces foo.wasm, hello.wasm
compile_wasm(["foo.wat", "hello.wat"])

import.txt

import "../wasm.tmake"