Ticket #31796 : make maxima output parseable.

- maxima.py : replace all whitespace sequences by a single space.
- maxima_lib : a single space joins the strings tepresenting the elements.
- Check and update the doctests and docstrings in various places :
    * src/doc/de/tutorial/tour_algebra.rst
    * src/doc/en/constructions/linear_algebra.rst
    * src/doc/en/tutorial/tour_algebra.rst
    * src/doc/es/tutorial/tour_algebra.rst
    * src/doc/fr/tutorial/tour_algebra.rst
    * src/doc/ja/tutorial/tour_algebra.rst
    * src/doc/pt/tutorial/tour_algebra.rst
    * src/doc/ru/tutorial/tour_algebra.rst
    * src/sage/calculus/calculus.py
    * src/sage/functions/bessel.py
    * src/sage/functions/orthogonal_polys.py
    * src/sage/interfaces/maxima.py
    * src/sage/interfaces/maxima_abstract.py
    * src/sage/interfaces/maxima_lib.py
    * src/sage/symbolic/assumptions.py
    * src/sage/symbolic/expression_conversions.py
- Document that output is parseable, doctests.

Note : space placement of MaximaElement conversions appears to be semi-random.
Thefore : src/sage/symbolic/assumptions.py : reformat the assumptions list.
To be seen in a followup ticket.

src/doc/de/tutorial/tour_algebra.rst

@@ -211,7 +211,7 @@ Lösung: Berechnen Sie die Laplace-Transformierte der ersten Gleichung
 
     sage: de1 = maxima("2*diff(x(t),t, 2) + 6*x(t) - 2*y(t)")
     sage: lde1 = de1.laplace("t","s"); lde1
-    2*((-%at('diff(x(t),t,1),t=0))+s^2*'laplace(x(t),t,s)-x(0)*s)-2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
+    2*((-%at('diff(x(t),t,1),t = 0))+s^2*'laplace(x(t),t,s)-x(0)*s) -2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
 
 Das ist schwierig zu lesen, es besagt jedoch, dass
 
@@ -225,9 +225,9 @@ Laplace-Transformierte der zweiten Gleichung:
 
 ::
 
-    sage: de2 = maxima("diff(y(t),t, 2) + 2*y(t) - 2*x(t)")
-    sage: lde2 = de2.laplace("t","s"); lde2
-    (-%at('diff(y(t),t,1),t=0))+s^2*'laplace(y(t),t,s)+2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s)-y(0)*s
+    sage: de1 = maxima("2*diff(x(t),t, 2) + 6*x(t) - 2*y(t)")
+    sage: lde1 = de1.laplace("t","s"); lde1
+    2*((-%at('diff(x(t),t,1),t = 0))+s^2*'laplace(x(t),t,s)-x(0)*s) -2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
 
 Dies besagt
 

src/doc/en/constructions/linear_algebra.rst

@@ -278,7 +278,7 @@ Another approach is to use the interface with Maxima:
     sage: A = maxima("matrix ([1, -4], [1, -1])")
     sage: eig = A.eigenvectors()
     sage: eig
-    [[[-sqrt(3)*%i,sqrt(3)*%i],[1,1]],[[[1,(sqrt(3)*%i+1)/4]],[[1,-(sqrt(3)*%i-1)/4]]]]
+    [[[-sqrt(3)*%i,sqrt(3)*%i],[1,1]], [[[1,(sqrt(3)*%i+1)/4]],[[1,-(sqrt(3)*%i-1)/4]]]]
 
 This tells us that :math:`\vec{v}_1 = [1,(\sqrt{3}i + 1)/4]` is
 an eigenvector of :math:`\lambda_1 = - \sqrt{3}i` (which occurs

src/doc/en/tutorial/tour_algebra.rst

@@ -218,7 +218,7 @@ the notation :math:`x=x_{1}`, :math:`y=x_{2}`):
 
     sage: de1 = maxima("2*diff(x(t),t, 2) + 6*x(t) - 2*y(t)")
     sage: lde1 = de1.laplace("t","s"); lde1
-    2*((-%at('diff(x(t),t,1),t=0))+s^2*'laplace(x(t),t,s)-x(0)*s)-2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
+    2*((-%at('diff(x(t),t,1),t = 0))+s^2*'laplace(x(t),t,s)-x(0)*s) -2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
 
 This is hard to read, but it says that
 
@@ -233,7 +233,7 @@ Laplace transform of the second equation:
 
     sage: de2 = maxima("diff(y(t),t, 2) + 2*y(t) - 2*x(t)")
     sage: lde2 = de2.laplace("t","s"); lde2
-    (-%at('diff(y(t),t,1),t=0))+s^2*'laplace(y(t),t,s)+2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s)-y(0)*s
+    (-%at('diff(y(t),t,1),t = 0))+s^2*'laplace(y(t),t,s) +2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s) -y(0)*s
 
 This says
 

src/doc/es/tutorial/tour_algebra.rst

@@ -198,7 +198,7 @@ la notación :math:`x=x_{1}`, :math:`y=x_{2}`):
 
     sage: de1 = maxima("2*diff(x(t),t, 2) + 6*x(t) - 2*y(t)")
     sage: lde1 = de1.laplace("t","s"); lde1
-    2*((-%at('diff(x(t),t,1),t=0))+s^2*'laplace(x(t),t,s)-x(0)*s)-2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
+    2*((-%at('diff(x(t),t,1),t = 0))+s^2*'laplace(x(t),t,s)-x(0)*s) -2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
 
 El resultado puede ser difícil de leer, pero significa que
 
@@ -213,7 +213,7 @@ Toma la transformada de Laplace de la segunda ecuación:
 
     sage: de2 = maxima("diff(y(t),t, 2) + 2*y(t) - 2*x(t)")
     sage: lde2 = de2.laplace("t","s"); lde2
-    (-%at('diff(y(t),t,1),t=0))+s^2*'laplace(y(t),t,s)+2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s)-y(0)*s
+    (-%at('diff(y(t),t,1),t = 0))+s^2*'laplace(y(t),t,s) +2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s) -y(0)*s
 
 Esto dice
 

src/doc/fr/tutorial/tour_algebra.rst

@@ -183,7 +183,7 @@ Solution : Considérons la transformée de Laplace de la première équation
 
     sage: de1 = maxima("2*diff(x(t),t, 2) + 6*x(t) - 2*y(t)")
     sage: lde1 = de1.laplace("t","s"); lde1
-    2*((-%at('diff(x(t),t,1),t=0))+s^2*'laplace(x(t),t,s)-x(0)*s)-2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
+    2*((-%at('diff(x(t),t,1),t = 0))+s^2*'laplace(x(t),t,s)-x(0)*s) -2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
 
 La réponse n'est pas très lisible, mais elle signifie que
 
@@ -198,7 +198,7 @@ la seconde équation :
 
     sage: de2 = maxima("diff(y(t),t, 2) + 2*y(t) - 2*x(t)")
     sage: lde2 = de2.laplace("t","s"); lde2
-    (-%at('diff(y(t),t,1),t=0))+s^2*'laplace(y(t),t,s)+2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s)-y(0)*s
+    (-%at('diff(y(t),t,1),t = 0))+s^2*'laplace(y(t),t,s) +2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s) -y(0)*s
 
 Ceci signifie
 

src/doc/ja/tutorial/tour_algebra.rst

@@ -214,7 +214,7 @@ Sageを使って常微分方程式を研究することもできる． :math:`x'
 
     sage: de1 = maxima("2*diff(x(t),t, 2) + 6*x(t) - 2*y(t)")
     sage: lde1 = de1.laplace("t","s"); lde1
-    2*((-%at('diff(x(t),t,1),t=0))+s^2*'laplace(x(t),t,s)-x(0)*s)-2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
+    2*((-%at('diff(x(t),t,1),t = 0))+s^2*'laplace(x(t),t,s)-x(0)*s) -2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
 
 この出力は読みにくいけれども，意味しているのは
 
@@ -226,9 +226,9 @@ Sageを使って常微分方程式を研究することもできる． :math:`x'
 
 ::
 
-    sage: de2 = maxima("diff(y(t),t, 2) + 2*y(t) - 2*x(t)")
-    sage: lde2 = de2.laplace("t","s"); lde2
-    (-%at('diff(y(t),t,1),t=0))+s^2*'laplace(y(t),t,s)+2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s)-y(0)*s
+    sage: de1 = maxima("2*diff(x(t),t, 2) + 6*x(t) - 2*y(t)")
+    sage: lde1 = de1.laplace("t","s"); lde1
+    2*((-%at('diff(x(t),t,1),t = 0))+s^2*'laplace(x(t),t,s)-x(0)*s) -2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
 
 意味するところは
 

src/doc/pt/tutorial/tour_algebra.rst

@@ -206,7 +206,7 @@ equação (usando a notação :math:`x=x_{1}`, :math:`y=x_{2}`):
 
     sage: de1 = maxima("2*diff(x(t),t, 2) + 6*x(t) - 2*y(t)")
     sage: lde1 = de1.laplace("t","s"); lde1
-    2*((-%at('diff(x(t),t,1),t=0))+s^2*'laplace(x(t),t,s)-x(0)*s)-2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
+    2*((-%at('diff(x(t),t,1),t = 0))+s^2*'laplace(x(t),t,s)-x(0)*s) -2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
 
 O resultado é um pouco difícil de ler, mas diz que
 
@@ -221,7 +221,7 @@ calcule a transformada de Laplace da segunda equação:
 
     sage: de2 = maxima("diff(y(t),t, 2) + 2*y(t) - 2*x(t)")
     sage: lde2 = de2.laplace("t","s"); lde2
-    (-%at('diff(y(t),t,1),t=0))+s^2*'laplace(y(t),t,s)+2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s)-y(0)*s
+    (-%at('diff(y(t),t,1),t = 0))+s^2*'laplace(y(t),t,s) +2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s) -y(0)*s
 
 O resultado significa que
 

src/doc/ru/tutorial/tour_algebra.rst

@@ -200,7 +200,7 @@ Sage может использоваться для решения диффер
 
     sage: de1 = maxima("2*diff(x(t),t, 2) + 6*x(t) - 2*y(t)")
     sage: lde1 = de1.laplace("t","s"); lde1
-    2*((-%at('diff(x(t),t,1),t=0))+s^2*'laplace(x(t),t,s)-x(0)*s)-2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
+    2*((-%at('diff(x(t),t,1),t = 0))+s^2*'laplace(x(t),t,s)-x(0)*s) -2*'laplace(y(t),t,s)+6*'laplace(x(t),t,s)
 
 Данный результат тяжело читаем, однако должен быть понят как
 
@@ -212,7 +212,7 @@ Sage может использоваться для решения диффер
 
     sage: de2 = maxima("diff(y(t),t, 2) + 2*y(t) - 2*x(t)")
     sage: lde2 = de2.laplace("t","s"); lde2
-    (-%at('diff(y(t),t,1),t=0))+s^2*'laplace(y(t),t,s)+2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s)-y(0)*s
+    (-%at('diff(y(t),t,1),t = 0))+s^2*'laplace(y(t),t,s) +2*'laplace(y(t),t,s)-2*'laplace(x(t),t,s) -y(0)*s
 
 Результат:
 

src/sage/calculus/calculus.py

@@ -2081,7 +2081,7 @@ def symbolic_expression_from_maxima_string(x, equals_sub=False, maxima=maxima):
         sage: sefms('?%at(f(x),x=2)#1')
         f(2) != 1
         sage: a = sage.calculus.calculus.maxima("x#0"); a
-        x#0
+        x # 0
         sage: a.sage()
         x != 0
 

src/sage/functions/bessel.py

@@ -1112,9 +1112,9 @@ def Bessel(*args, **kwds):
         sage: x,y = var('x,y')
         sage: f = maxima(Bessel(typ='K')(x,y))
         sage: f.derivative('_SAGE_VAR_x')
-        (%pi*csc(%pi*_SAGE_VAR_x)*('diff(bessel_i(-_SAGE_VAR_x,_SAGE_VAR_y),_SAGE_VAR_x,1)-'diff(bessel_i(_SAGE_VAR_x,_SAGE_VAR_y),_SAGE_VAR_x,1)))/2-%pi*bessel_k(_SAGE_VAR_x,_SAGE_VAR_y)*cot(%pi*_SAGE_VAR_x)
+        (%pi*csc(%pi*_SAGE_VAR_x) *('diff(bessel_i(-_SAGE_VAR_x,_SAGE_VAR_y),_SAGE_VAR_x,1) -'diff(bessel_i(_SAGE_VAR_x,_SAGE_VAR_y),_SAGE_VAR_x,1))) /2 -%pi*bessel_k(_SAGE_VAR_x,_SAGE_VAR_y)*cot(%pi*_SAGE_VAR_x)
         sage: f.derivative('_SAGE_VAR_y')
-        -(bessel_k(_SAGE_VAR_x+1,_SAGE_VAR_y)+bessel_k(_SAGE_VAR_x-1,_SAGE_VAR_y))/2
+        -(bessel_k(_SAGE_VAR_x+1,_SAGE_VAR_y)+bessel_k(_SAGE_VAR_x-1, _SAGE_VAR_y))/2
 
     Compute the particular solution to Bessel's Differential Equation that
     satisfies `y(1) = 1` and `y'(1) = 1`, then verify the initial conditions

src/sage/functions/orthogonal_polys.py

@@ -2338,7 +2338,7 @@ def __init__(self):
             sage: maxima(gen_laguerre(1,2,x, hold=True))
             3*(1-_SAGE_VAR_x/3)
             sage: maxima(gen_laguerre(n, a, gen_laguerre(n, a, x)))
-            gen_laguerre(_SAGE_VAR_n,_SAGE_VAR_a,gen_laguerre(_SAGE_VAR_n,_SAGE_VAR_a,_SAGE_VAR_x))
+            gen_laguerre(_SAGE_VAR_n,_SAGE_VAR_a, gen_laguerre(_SAGE_VAR_n,_SAGE_VAR_a,_SAGE_VAR_x))
         """
         OrthogonalFunction.__init__(self, "gen_laguerre", nargs=3, latex_name=r"L",
                 conversions={'maxima':'gen_laguerre', 'mathematica':'LaguerreL',

src/sage/interfaces/maxima.py

@@ -148,27 +148,28 @@
 
     sage: f = maxima('(x + 3*y + x^2*y)^3')
     sage: f.expand()
-    x^6*y^3+9*x^4*y^3+27*x^2*y^3+27*y^3+3*x^5*y^2+18*x^3*y^2+27*x*y^2+3*x^4*y+9*x^2*y+x^3
+    x^6*y^3+9*x^4*y^3+27*x^2*y^3+27*y^3+3*x^5*y^2+18*x^3*y^2+27*x*y^2 +3*x^4*y+9*x^2*y+x^3
     sage: f.subst('x=5/z')
     (5/z+(25*y)/z^2+3*y)^3
     sage: g = f.subst('x=5/z')
     sage: h = g.ratsimp(); h
-    (27*y^3*z^6+135*y^2*z^5+(675*y^3+225*y)*z^4+(2250*y^2+125)*z^3+(5625*y^3+1875*y)*z^2+9375*y^2*z+15625*y^3)/z^6
+    (27*y^3*z^6+135*y^2*z^5+(675*y^3+225*y)*z^4+(2250*y^2+125)*z^3 +(5625*y^3+1875*y)*z^2+9375*y^2*z+15625*y^3) /z^6
     sage: h.factor()
     (3*y*z^2+5*z+25*y)^3/z^6
 
 ::
 
     sage: eqn = maxima(['a+b*c=1', 'b-a*c=0', 'a+b=5'])
     sage: s = eqn.solve('[a,b,c]'); s
-    [[a=-(sqrt(79)*%i-11)/4,b=(sqrt(79)*%i+9)/4,c=(sqrt(79)*%i+1)/10],[a=(sqrt(79)*%i+11)/4,b=-(sqrt(79)*%i-9)/4,c=-(sqrt(79)*%i-1)/10]]
+    [[a = -(sqrt(79)*%i-11)/4,b = (sqrt(79)*%i+9)/4, c = (sqrt(79)*%i+1)/10], [a = (sqrt(79)*%i+11)/4,b = -(sqrt(79)*%i-9)/4, c = -(sqrt(79)*%i-1)/10]]
 
 Here is an example of solving an algebraic equation::
 
-    sage: maxima('x^2+y^2=1').solve('y')
-    [y=-sqrt(1-x^2),y=sqrt(1-x^2)]
+    sage: maxima('x^2+y^2=1').solve('y')                                            
+    [y = -sqrt(1-x^2),y = sqrt(1-x^2)]
     sage: maxima('x^2 + y^2 = (x^2 - y^2)/sqrt(x^2 + y^2)').solve('y')
-    [y=-sqrt(((-y^2)-x^2)*sqrt(y^2+x^2)+x^2),y=sqrt(((-y^2)-x^2)*sqrt(y^2+x^2)+x^2)]
+    [y = -sqrt(((-y^2)-x^2)*sqrt(y^2+x^2)+x^2), y = sqrt(((-y^2)-x^2)*sqrt(y^2+x^2)+x^2)]
+
 
 You can even nicely typeset the solution in latex::
 
@@ -197,9 +198,9 @@
     sage: f = maxima('x^3 * %e^(k*x) * sin(w*x)'); f
     x^3*%e^(k*x)*sin(w*x)
     sage: f.diff('x')
-    k*x^3*%e^(k*x)*sin(w*x)+3*x^2*%e^(k*x)*sin(w*x)+w*x^3*%e^(k*x)*cos(w*x)
+    k*x^3*%e^(k*x)*sin(w*x)+3*x^2*%e^(k*x)*sin(w*x)+w*x^3*%e^(k*x) *cos(w*x)
     sage: f.integrate('x')
-    (((k*w^6+3*k^3*w^4+3*k^5*w^2+k^7)*x^3+(3*w^6+3*k^2*w^4-3*k^4*w^2-3*k^6)*x^2+((-18*k*w^4)-12*k^3*w^2+6*k^5)*x-6*w^4+36*k^2*w^2-6*k^4)*%e^(k*x)*sin(w*x)+(((-w^7)-3*k^2*w^5-3*k^4*w^3-k^6*w)*x^3+(6*k*w^5+12*k^3*w^3+6*k^5*w)*x^2+(6*w^5-12*k^2*w^3-18*k^4*w)*x-24*k*w^3+24*k^3*w)*%e^(k*x)*cos(w*x))/(w^8+4*k^2*w^6+6*k^4*w^4+4*k^6*w^2+k^8)
+    (((k*w^6+3*k^3*w^4+3*k^5*w^2+k^7)*x^3 +(3*w^6+3*k^2*w^4-3*k^4*w^2-3*k^6)*x^2+((-18*k*w^4)-12*k^3*w^2+6*k^5)*x-6*w^4 +36*k^2*w^2-6*k^4) *%e^(k*x)*sin(w*x) +(((-w^7)-3*k^2*w^5-3*k^4*w^3-k^6*w)*x^3 +(6*k*w^5+12*k^3*w^3+6*k^5*w)*x^2+(6*w^5-12*k^2*w^3-18*k^4*w)*x-24*k*w^3 +24*k^3*w) *%e^(k*x)*cos(w*x)) /(w^8+4*k^2*w^6+6*k^4*w^4+4*k^6*w^2+k^8)
 
 ::
 
@@ -270,7 +271,7 @@
 
     sage: _ = maxima.eval("f(t) := t^5*exp(t)*sin(t)")
     sage: maxima("laplace(f(t),t,s)")
-    (360*(2*s-2))/(s^2-2*s+2)^4-(480*(2*s-2)^3)/(s^2-2*s+2)^5+(120*(2*s-2)^5)/(s^2-2*s+2)^6
+    (360*(2*s-2))/(s^2-2*s+2)^4-(480*(2*s-2)^3)/(s^2-2*s+2)^5 +(120*(2*s-2)^5)/(s^2-2*s+2)^6
     sage: print(maxima("laplace(f(t),t,s)"))
                                              3                 5
                360 (2 s - 2)    480 (2 s - 2)     120 (2 s - 2)
@@ -286,7 +287,7 @@
 ::
 
     sage: maxima("laplace(diff(x(t),t,2),t,s)")
-    (-%at('diff(x(t),t,1),t=0))+s^2*'laplace(x(t),t,s)-x(0)*s
+    (-%at('diff(x(t),t,1),t = 0))+s^2*'laplace(x(t),t,s)-x(0)*s
 
 It is difficult to read some of these without the 2d
 representation::
@@ -460,6 +461,16 @@
     sage: test.operator()._latex_() == 'C_+'
     True
 
+Test that the output is parseable (:trac:`31796`)::
+
+    sage: foo = maxima('a and (b or c)') ; foo
+    a and (b or c)
+    sage: bar = maxima(foo) ; bar
+    a and (b or c)
+    sage: bar == foo
+    True
+
+
 """
 
 #*****************************************************************************
@@ -681,9 +692,9 @@ def _expect_expr(self, expr=None, timeout=None):
             before integral or limit evaluation, for example):
             Is a positive or negative?
             sage: maxima.assume('a>0')
-            [a>0]
+            [a > 0]
             sage: maxima('integrate(1/(x^3*(a+b*x)^(1/3)),x)')
-            (-(b^2*log((b*x+a)^(2/3)+a^(1/3)*(b*x+a)^(1/3)+a^(2/3)))/(9*a^(7/3)))+(2*b^2*atan((2*(b*x+a)^(1/3)+a^(1/3))/(sqrt(3)*a^(1/3))))/(3^(3/2)*a^(7/3))+(2*b^2*log((b*x+a)^(1/3)-a^(1/3)))/(9*a^(7/3))+(4*b^2*(b*x+a)^(5/3)-7*a*b^2*(b*x+a)^(2/3))/(6*a^2*(b*x+a)^2-12*a^3*(b*x+a)+6*a^4)
+            (-(b^2*log((b*x+a)^(2/3)+a^(1/3)*(b*x+a)^(1/3)+a^(2/3)))/(9*a^(7/3))) +(2*b^2*atan((2*(b*x+a)^(1/3)+a^(1/3))/(sqrt(3)*a^(1/3))))/(3^(3/2)*a^(7/3)) +(2*b^2*log((b*x+a)^(1/3)-a^(1/3)))/(9*a^(7/3)) +(4*b^2*(b*x+a)^(5/3)-7*a*b^2*(b*x+a)^(2/3)) /(6*a^2*(b*x+a)^2-12*a^3*(b*x+a)+6*a^4)
             sage: maxima('integrate(x^n,x)')
             Traceback (most recent call last):
             ...
@@ -692,11 +703,11 @@ def _expect_expr(self, expr=None, timeout=None):
             integral or limit evaluation, for example):
             Is n equal to -1?
             sage: maxima.assume('n+1>0')
-            [n>-1]
+            [n > -1]
             sage: maxima('integrate(x^n,x)')
             x^(n+1)/(n+1)
             sage: maxima.forget([fact for fact in maxima.facts()])
-            [[a>0,n>-1]]
+            [[a > 0,n > -1]]
             sage: maxima.facts()
             []
             sage: var('a')
@@ -814,7 +825,7 @@ def _eval_line(self, line, allow_use_file=False,
         m = r.search(out)
         if m is not None:
             out = out[m.end():]
-        return re.sub(r'\s+', '', out)
+        return re.sub(r'\s+', ' ', out).rstrip()
 
     def _synchronize(self):
         """

src/sage/interfaces/maxima_abstract.py

@@ -516,7 +516,7 @@ def _equality_symbol(self):
              sage: var('x y')
              (x, y)
              sage: maxima(x == y)
-             _SAGE_VAR_x=_SAGE_VAR_y
+             _SAGE_VAR_x = _SAGE_VAR_y
         """
         return '='
 
@@ -533,7 +533,7 @@ def _inequality_symbol(self):
              sage: maxima._inequality_symbol()
              '#'
              sage: maxima((x != 1))
-             _SAGE_VAR_x#1
+             _SAGE_VAR_x # 1
         """
         return '#'
 
@@ -855,13 +855,13 @@ def de_solve(self, de, vars, ics=None):
         EXAMPLES::
 
             sage: maxima.de_solve('diff(y,x,2) + 3*x = y', ['x','y'], [1,1,1])
-            y=3*x-2*%e^(x-1)
+            y = 3*x-2*%e^(x-1)
             sage: maxima.de_solve('diff(y,x,2) + 3*x = y', ['x','y'])
-            y=%k1*%e^x+%k2*%e^-x+3*x
+            y = %k1*%e^x+%k2*%e^-x+3*x
             sage: maxima.de_solve('diff(y,x) + 3*x = y', ['x','y'])
-            y=(%c-3*((-x)-1)*%e^-x)*%e^x
+            y = (%c-3*((-x)-1)*%e^-x)*%e^x
             sage: maxima.de_solve('diff(y,x) + 3*x = y', ['x','y'],[1,1])
-            y=-%e^-1*(5*%e^x-3*%e*x-3*%e)
+            y = -%e^-1*(5*%e^x-3*%e*x-3*%e)
         """
         if not isinstance(vars, str):
             str_vars = '%s, %s'%(vars[1], vars[0])
@@ -899,14 +899,14 @@ def de_solve_laplace(self, de, vars, ics=None):
 
             sage: maxima.clear('x'); maxima.clear('f')
             sage: maxima.de_solve_laplace("diff(f(x),x,2) = 2*diff(f(x),x)-f(x)", ["x","f"], [0,1,2])
-            f(x)=x*%e^x+%e^x
+            f(x) = x*%e^x+%e^x
 
         ::
 
             sage: maxima.clear('x'); maxima.clear('f')
             sage: f = maxima.de_solve_laplace("diff(f(x),x,2) = 2*diff(f(x),x)-f(x)", ["x","f"])
             sage: f
-            f(x)=x*%e^x*('at('diff(f(x),x,1),x=0))-f(0)*x*%e^x+f(0)*%e^x
+            f(x) = x*%e^x*('at('diff(f(x),x,1),x = 0))-f(0)*x*%e^x+f(0)*%e^x
             sage: print(f)
                                                !
                                    x  d        !                  x          x
@@ -946,7 +946,7 @@ def solve_linear(self, eqns,vars):
             sage: eqns = ["x + z = y","2*a*x - y = 2*a^2","y - 2*z = 2"]
             sage: vars = ["x","y","z"]
             sage: maxima.solve_linear(eqns, vars)
-            [x=a+1,y=2*a,z=a-1]
+            [x = a+1,y = 2*a,z = a-1]
         """
         eqs = "["
         for i in range(len(eqns)):

src/sage/interfaces/maxima_lib.py

@@ -68,6 +68,15 @@
     sage: maxima_calculus("besselexpand:true")
     true
 
+The output is parseable (i. e. :trac:`31796` is fixed)::
+
+    sage: foo = maxima_calculus('a and (b or c)') ; foo
+    a and (b or c)
+    sage: bar = maxima_calculus(foo) ; bar
+    a and (b or c)
+    sage: bar == foo
+    True
+
 """
 
 # ****************************************************************************
@@ -458,7 +467,7 @@ def _eval_line(self, line, locals=None, reformat=True, **kwds):
                     maxima_eval("#$%s$" % statement)
         if not reformat:
             return result
-        return ''.join([x.strip() for x in result.split()])
+        return ' '.join([x.strip() for x in result.split()])
 
     eval = _eval_line
 
@@ -1394,12 +1403,12 @@ def max_at_to_sage(expr):
         sage: from sage.interfaces.maxima_lib import maxima_lib, max_at_to_sage
         sage: a=maxima_lib("'at(f(x,y,z),[x=1,y=2,z=3])")
         sage: a
-        'at(f(x,y,z),[x=1,y=2,z=3])
+        'at(f(x,y,z),[x = 1,y = 2,z = 3])
         sage: max_at_to_sage(a.ecl())
         f(1, 2, 3)
         sage: a=maxima_lib("'at(f(x,y,z),x=1)")
         sage: a
-        'at(f(x,y,z),x=1)
+        'at(f(x,y,z),x = 1)
         sage: max_at_to_sage(a.ecl())
         f(1, y, z)
     """