Build the prerequisites

1. Nu requires PCRE, the Perl-Compatible Regular Expression Library. Before building Nu, download and install PCRE, enabling UTF-8. Look for it at www.pcre.org.
To build a universal binary with UTF-8 support, use the following command:

% env CXXFLAGS="-arch i386 -arch ppc" \
      CFLAGS="-arch i386 -arch ppc" \
      LDFLAGS="-arch i386 -arch ppc" \
      ./configure --disable-dependency-tracking --enable-utf8

Don't forget to build PCRE with UTF-8 support. That's essential.
Subsequent build steps will fail if you don't do this.

If you are using a 10.4 PowerPC system to build universal binaries, you will also need to add the following flags to CXXFLAGS, CFLAGS, and LDFLAGS:

"-isysroot /Developer/SDKs/MacOSX10.4u.sdk"

When you install PCRE, it's best to put it in /usr/local (the default). If you put it anywhere else, you'll have to modify the Rakefile and Nukefile used to build Nu.

2. Important: Leopard (10.5) users should skip this step. Nu requires libffi. On Mac OS 10.5, libffi is included as a shared library, so 10.5 users should skip this step. But on Mac OS 10.4 and other systems, you may need to build your own libffi library. A version has been provided in the libffi directory. To build it, use the Ruby rake build tool and the included Rakefile.

% cd libffi; rake; cd ..

If you don't have rake on your system, get it with gem install rake or download it from rake.rubyforge.org.

Also, you may see some warning messages from libtool when you build libffi. It seems that they can be safely ignored. Here's what I see when I build libffi on my development systems:

[neon:~/Desktop/Nu/libffi] tim% rake
(in /Volumes/Neon/Users/tim/Desktop/Nu/libffi)
gcc -g -O3 -Wall -DMACOSX -Iinclude -I. -Isrc -arch i386 -arch ppc  -c -o src/types.o src/types.c
/opt/local/lib/ruby/gems/1.8/gems/rake-0.7.1/lib/rake.rb:728: warning: Insecure world writable dir /Volumes, mode 041777
gcc -g -O3 -Wall -DMACOSX -Iinclude -I. -Isrc -arch i386 -arch ppc  -c -o src/prep_cif.o src/prep_cif.c
gcc -g -O3 -Wall -DMACOSX -Iinclude -I. -Isrc -arch i386 -arch ppc  -c -o src/x86/ffi_darwin.o src/x86/ffi_darwin.c
gcc -g -O3 -Wall -DMACOSX -Iinclude -I. -Isrc -arch i386 -arch ppc  -c -o src/x86/darwin.o src/x86/darwin.S
gcc -g -O3 -Wall -DMACOSX -Iinclude -I. -Isrc -arch i386 -arch ppc  -c -o src/powerpc/ffi_darwin.o src/powerpc/ffi_darwin.c
gcc -g -O3 -Wall -DMACOSX -Iinclude -I. -Isrc -arch i386 -arch ppc  -c -o src/powerpc/darwin.o src/powerpc/darwin.S
gcc -g -O3 -Wall -DMACOSX -Iinclude -I. -Isrc -arch i386 -arch ppc  -c -o src/powerpc/darwin_closure.o src/powerpc/darwin_closure.S
libtool -static -o libffi.a src/types.o src/prep_cif.o src/x86/ffi_darwin.o src/x86/darwin.o src/powerpc/ffi_darwin.o src/powerpc/darwin.o src/powerpc/darwin_closure.o
libtool: warning for architecture: i386 same member name (darwin.o) in output file used for input files: src/x86/darwin.o and: src/powerpc/darwin.o (due to use of basename, truncation, blank padding or duplicate input files)
libtool: warning for architecture: i386 same member name (ffi_darwin.o) in output file used for input files: src/x86/ffi_darwin.o and: src/powerpc/ffi_darwin.o (due to use of basename, truncation, blank padding or duplicate input files)
libtool: warning for architecture: ppc same member name (darwin.o) in output file used for input files: src/x86/darwin.o and: src/powerpc/darwin.o (due to use of basename, truncation, blank padding or duplicate input files)
libtool: warning for architecture: ppc same member name (ffi_darwin.o) in output file used for input files: src/x86/ffi_darwin.o and: src/powerpc/ffi_darwin.o (due to use of basename, truncation, blank padding or duplicate input files)
ranlib libffi.a

Build Nu

3. Use make to build mininush, a minimal version of the Nu shell.

% make

4. Now use mininush to run nuke to complete the Nu build process. This builds Nu.framework, the Nu framework, and nush, the Nu shell.

 
% ./mininush tools/nuke

Install and Test Nu

5. Use mininush again to install Nu.framework, nush, and the Nu tools.

% ./mininush tools/nuke install

Since the copying step uses sudo, you will be prompted for your password.
The framework goes in /Library/Frameworks, executables go in /usr/local/bin, and some support files go to /usr/local/share.

6. Test your installation with nuke test. You should see results like these:

[neon:~/Desktop/Nu] tim% nuke test
nuke: nutest test/test_*.nu

TestArray: running
--- testCreate
TestArray: completed 1 tests/3 assertions/0 failures

TestControl: running
--- testCase
--- testCond
--- testFor
--- testForBreak
--- testForContinue
--- testIf
--- testLoopMacro
--- testUnless
--- testUntil
--- testUntilBreak
--- testUntilContinue
--- testWhile
--- testWhileBreak
--- testWhileContinue
TestControl: completed 14 tests/27 assertions/0 failures

TestDictionary: running
--- testCreate
--- testSet
TestDictionary: completed 2 tests/6 assertions/0 failures

TestExceptions: running
--- testRangeException
--- testUserRaisedException
--- testUserThrownException
--- testUserThrownObject
TestExceptions: completed 4 tests/16 assertions/0 failures

TestMacros: running
--- testBrokenFactorialMacro
--- testFactorialFunction
--- testFactorialMacro
--- testGensymInterpolation
--- testMacroImplementation
TestMacros: completed 5 tests/5 assertions/0 failures

TestMath: running
--- testAbs
--- testArithmeticOperators
--- testBooleanOperators
--- testComparisonOperators
--- testCos
--- testExp
--- testIntegerDivide
--- testIntegerMod
--- testLog
--- testShiftOperators
--- testSin
--- testSqrt
--- testSquare
TestMath: completed 13 tests/59 assertions/0 failures

TestRegex: running
--- testRegex
--- testScrape
TestRegex: completed 2 tests/3 assertions/0 failures

TestSwizzling: running
--- testClassMethodSwizzling
--- testInstanceMethodSwizzling
TestSwizzling: completed 2 tests/12 assertions/0 failures

TestTemplates: running
--- testCodeSubstitution
--- testCountingSubstitution
TestTemplates: completed 2 tests/2 assertions/0 failures

All: completed 45 tests/133 assertions/0 failures

SUCCESS (0 failures)

From now on, you can use the installed nush to run nuke. To see for yourself, rebuild everything from scratch:

% nuke clobber
% nuke
% nuke install
% nuke test

See the Nukefile for other useful tasks.