Issue 504b (JuliaPy#513)

* get docs working

* odd error

* odd error 2

* odd error 2

* simplify difference

* push change to POW

* version bump

* run doctest fix=true

* intercept sqrt, cbrt

Project.toml

@@ -1,6 +1,6 @@
 name = "SymPy"
 uuid = "24249f21-da20-56a4-8eb1-6a02cf4ae2e6"
-version = "1.1.9"
+version = "1.1.10"
 
 [deps]
 CommonEq = "3709ef60-1bee-4518-9f2f-acd86f176c50"

docs/src/Tutorial/basic_operations.md

@@ -515,7 +515,7 @@ julia> ex = sin(x)^2 + x^2
 x  + sin (x)
 
 julia> body = convert(Expr, ex)
-:(SymPy.__POW__(x, 2) + SymPy.__POW__(sin(x), 2))
+:(x ^ 2 + sin(x) ^ 2)
 
 julia> syms = Symbol.(free_symbols(ex))
 1-element Vector{Symbol}:

src/lambdify.jl

@@ -42,15 +42,15 @@ __ZERO__(xs...) = 0
 # not quite a match; NaN not θ(0) when evaluated at 0 w/o second argument
 __HEAVISIDE__ = (a...)  -> (a[1] < 0 ? 0 : (a[1] > 0 ? 1 : (length(a) > 1 ? a[2] : NaN)))
 __POW__(x, y::Int) = Base.literal_pow(^, x, Val(y)) # otherwise
-__POW__(a,b) = (a)^(b)
+__POW__(a,b) = (@show a, b; (a)^(b))
 #  __SYMPY__ALL__,
 fn_map = Dict(
     "Add" => :+,
     "Sub" => :-,
     "Mul" => :*, # :(SymPy.__PROD__)
     "Div" => :/,
-    #    "Pow" => :^,
-    "Pow" => :(SymPy.__POW__),
+    "Pow" => :^,
+    #"Pow" => :(SymPy.__POW__),
     "re"  => :real,
     "im"  => :imag,
     "Abs" => :abs,
@@ -134,6 +134,11 @@ function walk_expression(ex; values=Dict(), fns=Dict())
         return walk_expression.(Introspection.args(ex), values=values, fns=fns)
     elseif fn == "Indexed"
         return Expr(:ref, [walk_expression(a, values=values, fns=fns) for a in Introspection.args(ex)]...)
+    elseif fn == "Pow"
+        a, b = Introspection.args(ex)
+        b == 1//2 && return Expr(:call, :sqrt, walk_expression(a, values=values, fns=fns))
+        b == 1//3 && return Expr(:call, :cbrt, walk_expression(a, values=values, fns=fns))
+        return Expr(:call, :^,  [walk_expression(aᵢ, values=values, fns=fns) for aᵢ in (a,b)]...)
     elseif haskey(vals_map, fn)
         return vals_map[fn]
     end