1 files changed, 112 insertions, 4 deletions

diff --git a/attoconf/core.py b/attoconf/core.py
index 0c01d5e..8b53209 100644
--- a/attoconf/core.py
+++ b/attoconf/core.py
@@ -17,21 +17,48 @@
 
 from __future__ import print_function, division, absolute_import
 
+from collections import namedtuple
+import os
+import sys
+
+from .help import Help
+
+# Nothing to see here. Move along.
+Option = namedtuple('Option', ['type', 'init'])
+class ArgumentError(Exception): pass
+
+def as_var(name):
+    return name.lstrip('-').upper()
+
+def trim_trailing_slashes(path):
+    p, s = os.path.split(path)
+    if not s:
+        return p
+    return path
+
 class Project(object):
     ''' A Project is a directory and the list of options that can be set.
     '''
     __slots__ = (
+            'srcdir',
             'aliases',
             'options',
             'help',
+            'checks',
     )
     def __init__(self, srcdir):
         ''' A Project is initially constructed from just the source directory
         '''
+        self.srcdir = trim_trailing_slashes(srcdir)
+        self.aliases = {}
+        self.options = {}
+        self.help = Help()
+        self.checks = []
 
     def add_help(self, text, hidden):
         ''' Directly add a line of text to the help.
         '''
+        self.help.add_text(text, hidden)
 
     def add_alias(self, key, expansion, help, hidden):
         ''' Add an alias.
@@ -40,8 +67,17 @@ class Project(object):
 
             The expansion is a list of other options, which may be aliases.
         '''
-
-    def add_option(self, name, init, type, check, help, hidden):
+        if key in self.aliases:
+            raise KeyError(key)
+        expansion = list(expansion)
+        self.aliases[key] = expansion
+        if help is None:
+            help = 'alias for ' + ' '.join(expansion)
+        self.help.add_option(key, help, hidden)
+
+    def add_option(self, name, init, type, check,
+            help, hidden,
+            help_var=None, help_def=None):
         ''' Add an actual option.
 
             This must be passed with a =.
@@ -56,27 +92,99 @@ class Project(object):
 
             Additionally, a line of help is added, with additional formatting.
         '''
+        if name in self.options:
+            raise KeyError(name)
+        self.options[name] = Option(init=init, type=type)
+        self.checks.append(lambda bld: check(bld, bld.vars[as_var(name)][0]))
+        if help_var is None:
+            help_var = as_var(name)
+        if help_def is None:
+            help_def = init
+        if help_def is not None:
+            help = '%s [%s]' % (help, help_def)
+
+        if help_var != name:
+            help_opt = '%s=%s' % (name, help_var)
+        else:
+            help_opt = name
+        self.help.add_option(help_opt, help, hidden)
+
+    def do_help(self, opt):
+        ''' Pseudo type-hook to be registered for --help (calls sys.exit).
+        '''
+        if opt == 'default':
+            hidden = False
+        elif opt == 'hidden':
+            hidden = True
+        else:
+            raise ValueError
+        self.help.print(sys.stdout, hidden)
+        sys.exit()
 
 class Build(object):
     ''' A Build is a directory and set of options applied to a Project.
     '''
     __slots__ = (
+            'bindir',
             'project',
             'vars',
     )
     def __init__(self, project, bindir):
-        ''' A Build is initially constructed from
+        ''' A Build is initially constructed from a project and a build dir.
         '''
+        self.project = project
+        self.bindir = trim_trailing_slashes(bindir)
+        self.vars = {as_var(k): (o.init, 'default')
+                for k, o in project.options.iteritems()}
 
     def apply_arg(self, arg):
         ''' Parse a single argument, expanding aliases.
         '''
+        alias = self.project.aliases.get(arg)
+        if alias is not None:
+            for e in alias:
+                # TODO: catch recursive aliases
+                # or should they be caught earlier?
+                self.apply_arg(e)
+            return
+
+        if '=' not in arg:
+            if arg in self.project.options:
+                raise ArgumentError('Option %s requires an argument' % arg)
+            elif arg.startswith('-'):
+                raise ArgumentError('Unknown option %s' % arg)
+            else:
+                raise ArgumentError('Unknown environment variable %s' % arg)
+
+        k, a = arg.split('=', 1)
+        opt = self.project.options.get(k)
+        if opt is None:
+            raise sys.exit('Unknown option %s' % k)
+        self.vars[as_var(k)] = (opt.type(a), 'command-line')
 
     def finish(self):
         ''' With the current set of variables, run all the checks
             and presumably produce some sort of output.
         '''
+        for check in self.project.checks:
+            check(self)
 
     def configure(self, args, env):
-        ''' Automatically call apply_arg() a bunch of times, then finish().
+        ''' First apply variables from the environment,
+            then call apply_arg() a bunch of times, then finish().
+        '''
+        for k in self.vars:
+            val = env.get(k)
+            if val is not None:
+                self.vars[k] = (self.project.options[k].type(val), 'environment')
+
+        for arg in args:
+            self.apply_arg(arg)
+
+        self.finish()
+
+    def relative_source(self):
+        ''' Return a relative path from the build tree to the source tree.
         '''
+        return os.path.relpath(os.path.realpath(self.project.srcdir),
+                os.path.realpath(self.bindir))