fix some doctests

Author: fchapoton

demo-constructions-categories-short.rst

@@ -12,12 +12,12 @@ Demonstration: Algebraic constructions and categories
     sage: Px.<x> = QQ[]
     sage: Fx = Px.fraction_field()
 
-::
+.. ::
 
     sage: for category in Fx.categories(): print(category)
 
 ::
 
     sage: g = sage.categories.category.category_graph()
     sage: g.set_latex_options(format = "dot2tex")
-    sage: view(g, tightpage = True, viewer = "pdf")
+    sage: view(g, tightpage = True, viewer = "pdf")  # optional - dot2tex

demo-doc.rst

@@ -23,6 +23,8 @@ examples.
 Introspection::
 
     sage: m = matrix([[1/2,1],[2,1]]); m
+    [1/2   1]
+    [  2   1]
 
 .. skip:
 
@@ -34,6 +36,8 @@ Introspection::
 
     sage: g.
 
-Looking at the sources::
+Looking at the sources:
+
+.. skip::
 
     sage: m.det

demo-number-theory.rst

@@ -12,12 +12,12 @@ Construct an elliptic curve using John Cremona's table::
 
 Use *matplotlib* to plot it::
 
-    sage: plot(E,thickness=3)
+    sage: E.plot(thickness=3)
 
 Use *mwrank* to do a 2-descent::
 
     sage: print(E.mwrank())
-    Curve [0,1,1,-2,0] :    Rank = 2
+    Curve [0,1,1,-2,0] : ...
 
 *PARI* to compute Fourier coefficients `a_n`::
 
@@ -36,4 +36,4 @@ Use *mwrank* to do a 2-descent::
 
 *Magma* to compute the rank of the 3-selmer group::
 
-    sage: magma(E).ThreeSelmerGroup()
+    sage: magma(E).ThreeSelmerGroup()  # optional - magma

demo-plot-short.rst

@@ -7,19 +7,20 @@ Demonstration: Plots (short version)
 Some nice plots::
 
     sage: plot(sin(x), -2*pi, 2*pi, fill = 'axis')
+    Graphics object consisting of 2 graphics primitives
 
 Taylor approximation::
 
     sage: f = sin(x)
     sage: g = f.taylor(x,0,3)
     sage: plot(g, -2*pi, 2*pi)
+    Graphics object consisting of 1 graphics primitive
 
 All the way to a full featured applet::
 
-    sage: %hide
-    sage: var('x')
-    sage: @interact
-    sage: def g(f=sin(x), c=0, n=(1..30),
+    sage: x = var('x')
+    sage: @interact                  # not tested
+    ....: def g(f=sin(x), c=0, n=(1..30),
     ....:       xinterval=range_slider(-10, 10, 1, default=(-8,8), label="x-interval"),
     ....:       yinterval=range_slider(-50, 50, 1, default=(-3,3), label="y-interval")):
     ....:     x0 = c
@@ -31,6 +32,5 @@ All the way to a full featured applet::
     ....:     ft = f.taylor(x,x0,degree)
     ....:     pt = plot(ft, xmin, xmax, color='red', thickness=2, fill=f)
     ....:     show(dot + p + pt, ymin=ymin, ymax=ymax, xmin=xmin, xmax=xmax)
-    ....:     html('$f(x)\;=\;%s$'%latex(f))
-    ....:     html('$P_{%s}(x)\;=\;%s+R_{%s}(x)$'%(degree,latex(ft),degree))
-
+    ....:     html(r'$f(x)\;=\;%s$'%latex(f))
+    ....:     html(r'$P_{%s}(x)\;=\;%s+R_{%s}(x)$'%(degree,latex(ft),degree))

demo-symbolics.rst

@@ -15,9 +15,11 @@ petits.
 Une expression::
 
     sage: f = cos(x)^6 + sin(x)^6 + 3 * sin(x)^2 * cos(x)^2; f
-    sin(x)^6 + cos(x)^6 + 3*sin(x)^2*cos(x)^2
+    cos(x)^6 + sin(x)^6 + 3*cos(x)^2*sin(x)^2
 
-La même après avoir configuré les affichages en latex::
+La même après avoir configuré les affichages en latex:
+
+.. skip::
 
     sage: %display latex
     sage: f