From 40cc8d00b69d19864ada7c07a2a759dd03632a23 Mon Sep 17 00:00:00 2001
From: Bertrand Benjamin <benjamin.bertrand@opytex.org>
Date: Mon, 17 Sep 2018 18:18:29 +0200
Subject: [PATCH] basic simplify and explain methods for Expression

---
 mapytex/calculus/API/__init__.py   | 19 ++++++++
 mapytex/calculus/API/expression.py | 72 ++++++++++++++++++++++++------
 mapytex/calculus/API/renders.py    | 37 +++++++++++++++
 3 files changed, 115 insertions(+), 13 deletions(-)
 create mode 100644 mapytex/calculus/API/__init__.py
 create mode 100644 mapytex/calculus/API/renders.py

diff --git a/mapytex/calculus/API/__init__.py b/mapytex/calculus/API/__init__.py
new file mode 100644
index 0000000..ebce9c7
--- /dev/null
+++ b/mapytex/calculus/API/__init__.py
@@ -0,0 +1,19 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+# vim:fenc=utf-8
+#
+# Copyright © 2017 lafrite <lafrite@Poivre>
+#
+# Distributed under terms of the MIT license.
+
+"""
+
+"""
+
+from .expression import Expression
+
+
+# -----------------------------
+# Reglages pour 'vim'
+# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
+# cursor: 16 del
diff --git a/mapytex/calculus/API/expression.py b/mapytex/calculus/API/expression.py
index b026a55..0b8dd05 100644
--- a/mapytex/calculus/API/expression.py
+++ b/mapytex/calculus/API/expression.py
@@ -10,9 +10,8 @@
 Expression
 
 """
-from ..core import Tree, compute, tree2txt, tree2tex
-
-
+from ..core import Tree, compute
+from .renders import renders
 
 class Expression(object):
 
@@ -25,19 +24,20 @@ class Expression(object):
     >>> e2 = e.simplify()
     >>> print(e2)
     14
-    >>> e2.explain()
-    '2 + 3 * 4'
-    '2 + 12'
-    '15'
-
+    >>> for s in e2.explain():
+    ...    print(s)
+    2 + 3 * 4
+    2 + 12
+    14
     """
 
-    RENDER = tree2txt
+    RENDER = 'txt'
 
-    def __init__(self, tree):
+    def __init__(self, tree, ancestor=None):
         """
         """
         self._tree = tree
+        self._ancestor = ancestor
 
     @classmethod
     def from_str(cls,  string):
@@ -69,20 +69,66 @@ class Expression(object):
         :param render: render function Tree -> str
 
         :example:
+        >>> Expression.RENDER
+        'txt'
         >>> e = Expression.from_str("2+3*4")
         >>> print(e)
         2 + 3 * 4
-        >>> Expression.set_render(tree2tex)
+        >>> Expression.set_render('tex')
+        >>> Expression.RENDER
+        'tex'
         >>> print(e)
         2 + 3 \\times 4
         """
         cls.RENDER = render
 
     def __str__(self):
-        return self.__class__.RENDER(self._tree)
+        return renders[self.RENDER](self._tree)
 
     def __repr__(self):
-        return f"<Tree {self.__class__.RENDER(self._tree)}>"
+        return f"<Exp: {renders[self.RENDER](self._tree)}>"
+
+    def simplify(self):
+        """ Compute as much as possible the expression
+
+        :return: an expression
+
+        :example:
+        >>> e = Expression.from_str("2+3*4")
+        >>> e
+        <Exp: 2 + 3 \\times 4>
+        >>> f = e.simplify()
+        >>> f
+        <Exp: 14>
+        >>> f._ancestor
+        <Exp: 2 + 12>
+        """
+        try:
+            t = self._tree.apply_on_last_level(compute)
+        except AttributeError:
+            return self
+        else:
+            e = Expression(t, ancestor=self)
+            return e.simplify()
+
+    def explain(self):
+        """ Yield every calculus step which have lead to self
+        
+        :example:
+        >>> e = Expression.from_str("2+3*4")
+        >>> f = e.simplify()
+        >>> for s in f.explain():
+        ...     print(s)
+        2 + 3 * 4
+        2 + 12
+        14
+        """
+        try:
+            yield from self._ancestor.explain()
+        except AttributeError:
+            yield self
+        else:
+            yield self
 
 # -----------------------------
 # Reglages pour 'vim'
diff --git a/mapytex/calculus/API/renders.py b/mapytex/calculus/API/renders.py
new file mode 100644
index 0000000..6332259
--- /dev/null
+++ b/mapytex/calculus/API/renders.py
@@ -0,0 +1,37 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+# vim:fenc=utf-8
+#
+# Copyright © 2017 lafrite <lafrite@Poivre>
+#
+# Distributed under terms of the MIT license.
+
+"""
+Expression
+
+"""
+from ..core import tree2txt, tree2tex
+
+def _txt(mo_tree):
+    """ txt render for MOs or Trees"""
+    try:
+        return tree2txt(mo_tree)
+    except AttributeError:
+        return str(mo_tree)
+
+def _tex(mo_tree):
+    """ Tex render for MOs or Trees"""
+    try:
+        return tree2tex(mo_tree)
+    except AttributeError:
+        return str(mo_tree)
+
+renders = {
+    'txt': _txt,
+    'tex': _tex,
+}
+
+# -----------------------------
+# Reglages pour 'vim'
+# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
+# cursor: 16 del