Use Metatheory.jl 3.0 rule object

Project.toml

@@ -15,6 +15,7 @@ DynamicPolynomials = "7c1d4256-1411-5781-91ec-d7bc3513ac07"
 IfElse = "615f187c-cbe4-4ef1-ba3b-2fcf58d6d173"
 LabelledArrays = "2ee39098-c373-598a-b85f-a56591580800"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+Metatheory = "e9d8d322-4543-424a-9be4-0cc815abe26c"
 MultivariatePolynomials = "102ac46a-7ee4-5c85-9060-abc95bfdeaa3"
 NaNMath = "77ba4419-2d1f-58cd-9bb1-8ffee604a2e3"
 Setfield = "efcf1570-3423-57d1-acb7-fd33fddbac46"
@@ -43,7 +44,7 @@ Setfield = "0.7, 0.8, 1"
 SpecialFunctions = "0.10, 1.0, 2"
 StaticArrays = "0.12, 1.0"
 SymbolicIndexingInterface = "0.3"
-TermInterface = "0.4"
+TermInterface = "2.0"
 TimerOutputs = "0.5"
 Unityper = "0.1.2"
 julia = "1.3"

docs/src/manual/interface.md

@@ -13,6 +13,20 @@ You can read the documentation of [TermInterface.jl](https://github.com/JuliaSym
 
 ## SymbolicUtils.jl only methods
 
-`promote_symtype(f, arg_symtypes...)`
+### `symtype(x)`
+
+Returns the 
+[numeric type](https://docs.julialang.org/en/v1/base/numbers/#Standard-Numeric-Types) 
+of `x`. By default this is just `typeof(x)`.
+Define this for your symbolic types if you want [`SymbolicUtils.simplify`](@ref) to apply rules
+specific to numbers (such as commutativity of multiplication). Or such
+rules that may be implemented in the future.
+
+### `issym(x)`
+
+Returns `true` if `x` is a `Sym`. If `true`, `nameof` must be defined
+on `x` and must return a `Symbol`.
+
+### `promote_symtype(f, arg_symtypes...)`
 
 Returns the appropriate output type of applying `f` on arguments of type `arg_symtypes`.

docs/src/manual/representation.md

@@ -4,7 +4,7 @@ Performance of symbolic simplification depends on the datastructures used to rep
 
 The most basic term representation simply holds a function call and stores the function and the arguments it is called with. This is done by the `Term` type in SymbolicUtils. Functions that aren't commutative or associative, such as `sin` or `hypot` are stored as `Term`s. Commutative and associative operations like `+`, `*`, and their supporting operations like `-`, `/` and `^`, when used on terms of type `<:Number`, stand to gain from the use of more efficient datastrucutres.
 
-All term representations must support `operation` and `arguments` functions. And they must define `istree` to return `true` when called with an instance of the type. Generic term-manipulation programs such as the rule-based rewriter make use of this interface to inspect expressions. In this way, the interface wins back the generality lost by having a zoo of term representations instead of one. (see [interface](/interface/) section for more on this.)
+All term representations must support `operation` and `arguments` functions. And they must define `iscall` and `isexpr` to return `true` when called with an instance of the type. Generic term-manipulation programs such as the rule-based rewriter make use of this interface to inspect expressions. In this way, the interface wins back the generality lost by having a zoo of term representations instead of one. (see [interface](/interface/) section for more on this.)
 
 
 ### Preliminary representation of arithmetic

src/SymbolicUtils.jl

@@ -16,8 +16,8 @@ using SymbolicIndexingInterface
 import Base: +, -, *, /, //, \, ^, ImmutableDict
 using ConstructionBase
 using TermInterface
-import TermInterface: iscall, isexpr, issym, symtype, head, children,
-                      operation, arguments, metadata, maketerm
+import TermInterface: iscall, isexpr, head, children,
+                      operation, arguments, metadata, maketerm, sorted_arguments
 
 const istree = iscall
 Base.@deprecate_binding istree iscall

src/code.jl

@@ -9,7 +9,7 @@ export toexpr, Assignment, (←), Let, Func, DestructuredArgs, LiteralExpr,
 import ..SymbolicUtils
 import ..SymbolicUtils.Rewriters
 import SymbolicUtils: @matchable, BasicSymbolic, Sym, Term, iscall, operation, arguments, issym,
-                      symtype, similarterm, sorted_arguments, metadata, isterm, term, maketerm
+                      symtype, sorted_arguments, metadata, isterm, term, maketerm
 
 ##== state management ==##
 
@@ -115,7 +115,7 @@ function function_to_expr(op, O, st)
     (get(st.rewrites, :nanmath, false) && op in NaNMathFuns) || return nothing
     name = nameof(op)
     fun = GlobalRef(NaNMath, name)
-    args = map(Base.Fix2(toexpr, st), arguments(O))
+    args = map(Base.Fix2(toexpr, st), sorted_arguments(O))
     expr = Expr(:call, fun)
     append!(expr.args, args)
     return expr
@@ -138,7 +138,7 @@ function function_to_expr(op::Union{typeof(*),typeof(+)}, O, st)
 end
 
 function function_to_expr(::typeof(^), O, st)
-    args = arguments(O)
+    args = sorted_arguments(O)
     if length(args) == 2 && args[2] isa Real && args[2] < 0
         ex = args[1]
         if args[2] == -1
@@ -151,7 +151,7 @@ function function_to_expr(::typeof(^), O, st)
 end
 
 function function_to_expr(::typeof(SymbolicUtils.ifelse), O, st)
-    args = arguments(O)
+    args = sorted_arguments(O)
     :($(toexpr(args[1], st)) ? $(toexpr(args[2], st)) : $(toexpr(args[3], st)))
 end
 
@@ -183,7 +183,7 @@ function toexpr(O, st)
         return expr′
     else
         !iscall(O) && return O
-        args = arguments(O)
+        args = sorted_arguments(O)
         return Expr(:call, toexpr(op, st), map(x->toexpr(x, st), args)...)
     end
 end
@@ -693,8 +693,8 @@ end
 function _cse!(mem, expr)
     iscall(expr) || return expr
     op = _cse!(mem, operation(expr))
-    args = map(Base.Fix1(_cse!, mem), arguments(expr))
-    t = similarterm(expr, op, args)
+    args = map(Base.Fix1(_cse!, mem), sorted_arguments(expr))
+    t = maketerm(typeof(expr), op, args, nothing)
 
     v, dict = mem
     update! = let v=v, t=t
@@ -716,7 +716,7 @@ end
 
 function _cse(exprs::AbstractArray)
     letblock = cse(Term{Any}(tuple, vec(exprs)))
-    letblock.pairs, reshape(arguments(letblock.body), size(exprs))
+    letblock.pairs, reshape(sorted_arguments(letblock.body), size(exprs))
 end
 
 function cse(x::MakeArray)
@@ -763,9 +763,7 @@ function cse_block!(assignments, counter, names, name, state, x)
         if isterm(x)
             return term(operation(x), args...)
         else
-            return maketerm(typeof(x), operation(x),
-                               args, symtype(x),
-                               metadata(x))
+            return maketerm(typeof(x), operation(x), args, metadata(x))
         end
     else
         return x

src/matchers.jl

@@ -85,7 +85,7 @@ function matcher(segment::Segment)
 end
 
 function term_matcher(term)
-    matchers = (matcher(operation(term)), map(matcher, arguments(term))...,)
+    matchers = (matcher(operation(term)), map(matcher, sorted_arguments(term))...,)
     function term_matcher(success, data, bindings)
 
         !islist(data) && return nothing

src/ordering.jl

@@ -84,7 +84,7 @@ function <ₑ(a::BasicSymbolic, b::BasicSymbolic)
     bw = monomial_lt(db, da)
     if fw === bw && !isequal(a, b)
         if _arglen(a) == _arglen(b)
-            return (operation(a), arguments(a)...,) <ₑ (operation(b), arguments(b)...,)
+            return (operation(a), sorted_arguments(a)...,) <ₑ (operation(b), sorted_arguments(b)...,)
         else
             return _arglen(a) < _arglen(b)
         end

src/polyform.jl

@@ -103,7 +103,7 @@ function polyize(x, pvar2sym, sym2term, vtype, pow, Fs, recurse)
         end
 
         op = operation(x)
-        args = arguments(x)
+        args = sorted_arguments(x)
 
         local_polyize(y) = polyize(y, pvar2sym, sym2term, vtype, pow, Fs, recurse)
 
@@ -121,7 +121,6 @@ function polyize(x, pvar2sym, sym2term, vtype, pow, Fs, recurse)
                 maketerm(typeof(x),
                          op,
                          map(a->PolyForm(a, pvar2sym, sym2term, vtype; Fs, recurse), args),
-                         symtype(x),
                          metadata(x))
             else
                 x
@@ -176,18 +175,18 @@ isexpr(x::PolyForm) = true
 iscall(x::Type{<:PolyForm}) = true
 iscall(x::PolyForm) = true
 
-function maketerm(::Type{<:PolyForm}, f, args, symtype, metadata)
-    basicsymbolic(t, f, args, symtype, metadata)
+function maketerm(t::Type{<:PolyForm}, f, args, metadata)
+    # TODO: this looks uncovered.
+    basicsymbolic(f, args, nothing, metadata)
 end
-function maketerm(::Type{<:PolyForm}, f::Union{typeof(*), typeof(+), typeof(^)},
-                     args, symtype, metadata)
+function maketerm(::Type{<:PolyForm}, f::Union{typeof(*), typeof(+), typeof(^)}, args, metadata)
     f(args...)
 end
 
 head(::PolyForm) = PolyForm
 operation(x::PolyForm) = MP.nterms(x.p) == 1 ? (*) : (+)
 
-function arguments(x::PolyForm{T}) where {T}
+function TermInterface.arguments(x::PolyForm{T}) where {T}
 
     function is_var(v)
         MP.nterms(v) == 1 &&
@@ -231,10 +230,7 @@ function arguments(x::PolyForm{T}) where {T}
                  PolyForm{T}(t, x.pvar2sym, x.sym2term, nothing)) for t in ts]
     end
 end
-
-sorted_arguments(x::PolyForm) = arguments(x)
-
-children(x::PolyForm) = [operation(x); arguments(x)]
+children(x::PolyForm) = arguments(x)
 
 Base.show(io::IO, x::PolyForm) = show_term(io, x)
 
@@ -255,7 +251,7 @@ function unpolyize(x)
     # we need a special makterm here because the default one used in Postwalk will call
     # promote_symtype to get the new type, but we just want to forward that in case
     # promote_symtype is not defined for some of the expressions here.
-    Postwalk(identity, maketerm=(T,f,args,sT,m) -> maketerm(T, f, args, symtype(x), m))(x)
+    Postwalk(identity, maketerm=(T,f,args,m) -> maketerm(T, f, args, m))(x)
 end
 
 function toterm(x::PolyForm)
@@ -307,7 +303,8 @@ function add_divs(x, y)
     end
 end
 
-function frac_maketerm(T, f, args, stype, metadata)
+function frac_maketerm(T, f, args, metadata)
+    # TODO add stype to T?
     if f in (*, /, \, +, -)
         f(args...)
     elseif f == (^)
@@ -317,7 +314,7 @@ function frac_maketerm(T, f, args, stype, metadata)
             args[1]^args[2]
         end
     else
-        maketerm(T, f, args, stype, metadata)
+        maketerm(T, f, args, metadata)
     end
 end
 
@@ -394,7 +391,7 @@ function has_div(x)
 end
 
 flatten_pows(xs) = map(xs) do x
-    ispow(x) ? Iterators.repeated(arguments(x)...) : (x,)
+    ispow(x) ? Iterators.repeated(sorted_arguments(x)...) : (x,)
 end |> Iterators.flatten |> a->collect(Any,a)
 
 coefftype(x::PolyForm) = coefftype(x.p)