ENH: Interface for R

nipype/interfaces/r.py

@@ -0,0 +1,129 @@
+# -*- coding: utf-8 -*-
+# emacs: -*- mode: python; py-indent-offset: 4; indent-tabs-mode: nil -*-
+# vi: set ft=python sts=4 ts=4 sw=4 et:
+"""Interfaces to run R scripts."""
+import os
+
+from .. import config
+from .base import (
+    CommandLineInputSpec,
+    InputMultiPath,
+    isdefined,
+    CommandLine,
+    traits,
+    File,
+    Directory,
+)
+
+
+def get_r_command():
+    if "NIPYPE_NO_R" in os.environ:
+        return None
+    try:
+        r_cmd = os.environ["RCMD"]
+    except:
+        r_cmd = "R"
+    return r_cmd
+
+
+no_r = get_r_command() is None
+
+
+class RInputSpec(CommandLineInputSpec):
+    """ Basic expected inputs to R interface """
+
+    script = traits.Str(
+        argstr='-e "%s"', desc="R code to run", mandatory=True, position=-1
+    )
+    # non-commandline options
+    rfile = traits.Bool(True, desc="Run R using R script", usedefault=True)
+    script_file = File(
+        "pyscript.R", usedefault=True, desc="Name of file to write R code to"
+    )
+
+
+class RCommand(CommandLine):
+    """Interface that runs R code
+
+    >>> import nipype.interfaces.r as r
+    >>> r = r.RCommand(rfile=False)  # don't write script file
+    >>> r.inputs.script = "Sys.getenv('USER')"
+    >>> out = r.run()  # doctest: +SKIP
+    """
+
+    _cmd = "R"
+    _default_r_cmd = None
+    _default_rfile = None
+    input_spec = RInputSpec
+
+    def __init__(self, r_cmd=None, **inputs):
+        """initializes interface to r
+        (default 'R')
+        """
+        super(RCommand, self).__init__(**inputs)
+        if r_cmd and isdefined(r_cmd):
+            self._cmd = r_cmd
+        elif self._default_r_cmd:
+            self._cmd = self._default_r_cmd
+
+        if self._default_rfile and not isdefined(self.inputs.rfile):
+            self.inputs.rfile = self._default_rfile
+
+        # For r commands force all output to be returned since r
+        # does not have a clean way of notifying an error
+        self.terminal_output = "allatonce"
+
+    @classmethod
+    def set_default_r_cmd(cls, r_cmd):
+        """Set the default R command line for R classes.
+
+        This method is used to set values for all R
+        subclasses.  However, setting this will not update the output
+        type for any existing instances.  For these, assign the
+        <instance>.inputs.r_cmd.
+        """
+        cls._default_r_cmd = r_cmd
+
+    @classmethod
+    def set_default_rfile(cls, rfile):
+        """Set the default R script file format for R classes.
+
+        This method is used to set values for all R
+        subclasses.  However, setting this will not update the output
+        type for any existing instances.  For these, assign the
+        <instance>.inputs.rfile.
+        """
+        cls._default_rfile = rfile
+
+    def _run_interface(self, runtime):
+        self.terminal_output = "allatonce"
+        runtime = super(RCommand, self)._run_interface(runtime)
+        if "R code threw an exception" in runtime.stderr:
+            self.raise_exception(runtime)
+        return runtime
+
+    def _format_arg(self, name, trait_spec, value):
+        if name in ["script"]:
+            argstr = trait_spec.argstr
+            return self._gen_r_command(argstr, value)
+        return super(RCommand, self)._format_arg(name, trait_spec, value)
+
+    def _gen_r_command(self, argstr, script_lines):
+        """ Generates commands and, if rfile specified, writes it to disk."""
+        if not self.inputs.rfile:
+            # replace newlines with ;, strip comments
+            script = "; ".join([
+                        line
+                        for line in script_lines.split("\n")
+                        if not line.strip().startswith("#")
+                    ])
+            # escape " and $
+            script = script.replace('"','\\"')
+            script = script.replace('$','\\$')
+        else:
+            script_path = os.path.join(os.getcwd(), self.inputs.script_file)
+            with open(script_path, "wt") as rfile:
+                rfile.write(script_lines)
+            script = "source('%s')" % script_path
+
+        return argstr % script