George and I debugged rewriting. Incorrect type passed to resulting t…

…erm meant typed rewriting would fail

src/acset2symbolic.jl

@@ -33,12 +33,12 @@ function to_symbolics(d::SummationDecapode, symvar_lookup::Dict{Symbol, Symbolic
 
   op_sym = getfield(@__MODULE__, d[op_index, :op1])
 
-  @info typeof(op_sym)
-
-  rhs = SymbolicUtils.Term{Number}(op_sym, [input_sym])
+  S = promote_symtype(op_sym, input_sym)
+  rhs = SymbolicUtils.Term{S}(op_sym, [input_sym])
   SymbolicUtils.Term{Number}(DECA_EQUALITY_SYMBOL, [output_sym, rhs])
 end
 
+# TODO add promote_symtype as Op1
 function to_symbolics(d::SummationDecapode, symvar_lookup::Dict{Symbol, SymbolicUtils.BasicSymbolic}, op_index::Int, ::Val{:Op2})
   input1_sym = symvar_lookup[d[d[op_index, :proj1], :name]]
   input2_sym = symvar_lookup[d[d[op_index, :proj2], :name]]
@@ -47,7 +47,8 @@ function to_symbolics(d::SummationDecapode, symvar_lookup::Dict{Symbol, Symbolic
 
   op_sym = getfield(@__MODULE__, d[op_index, :op2])
 
-  rhs = SymbolicUtils.Term{Number}(op_sym, [input1_sym, input2_sym])
+  S = promote_symtype(op_sym, input1_sym, input2_sym)
+  rhs = SymbolicUtils.Term{S}(op_sym, [input1_sym, input2_sym])
   SymbolicUtils.Term{Number}(DECA_EQUALITY_SYMBOL, [output_sym, rhs])
 end
 
@@ -56,7 +57,9 @@ function to_symbolics(d::SummationDecapode, symvar_lookup::Dict{Symbol, Symbolic
   syms_array = [symvar_lookup[var] for var in d[d[incident(d, op_index, :summation), :summand], :name]]
   output_sym = symvar_lookup[d[d[op_index, :sum], :name]]
 
-  rhs = SymbolicUtils.Term{Number}(+, syms_array)
+  # TODO pls test
+  S = promote_symtype(+, syms_array...)
+  rhs = SymbolicUtils.Term{S}(+, syms_array)
   SymbolicUtils.Term{Number}(DECA_EQUALITY_SYMBOL, [output_sym, rhs])
 end
 

src/sym_rewrite.jl

@@ -1,14 +1,15 @@
+using Test
 using DiagrammaticEquations
 using SymbolicUtils
+using SymbolicUtils: Fixpoint, Prewalk, Postwalk, Chain, symtype, promote_symtype
 using MLStyle
 
 Heat = @decapode begin
   C::Form0
   G::Form1
   D::Constant
   ∂ₜ(G) == D*Δ(d(C))
-end
-
+end;
 infer_types!(Heat)
 
 Brusselator = @decapode begin
@@ -52,13 +53,60 @@ test = to_acset(Phytodynamics, symbolic_rewriting(Phytodynamics))
 
 # openers = [lap_0_rule, lap_1_rule, lap_2_rule]
 
-r = rules(Δ, Val(1))
 
+# it seems that type-instability or improper type promotion is happening. expressions derived from this have BasicSymbolic{Number} type, which means we can't conditionally rewrite on forms.
 heat_exprs = symbolic_rewriting(Heat)
+sub = heat_exprs[1].arguments[2].arguments[2]
+
+a, b = @syms a::Scalar b::Scalar
+u, v = @syms u::PrimalForm{0, :X, 2} du::PrimalForm{1, :X, 2}
+
+r = rules(Δ, Val(1))
+
+# rule without predication works
+R = @rule Δ(~x) => ★(d(★(d(~x))))
+rwR = Fixpoint(Prewalk(Chain([R])))
+
+R(Δ(d(u)))
+
+# since promote_symtype(d(u)) returns Any while promote_symtype(d, u). I wonder
+# if `d(u)` is not subjected to `symtype`
+
+Rp = @rule Δ(~x::isForm1) => "Success"
+Rp(Δ(v)) # works
+Rp(Δ(d(u))) # works
+
+Rp1 = @rule Δ(~x::isForm1) => ★(d(★(d(~x))))
+
+Rp1(Δ(v)) # works
+Rp1(Δ(d(u))) # works
+rwRp1 = Fixpoint(Prewalk(Chain([Rp1])))
+rwRp1(Δ(d(u)))
+
+rwr = Fixpoint(Prewalk(Chain(r)))
+rwr(heat_exprs[1]) # THIS WORKS!
+
+rwr(Δ(d(u))) # rwr
+rwr(heat_exprs[1].arguments[2])
+
+r[2](Δ(d(u))) # works
+
+
+# rwR(heat_exprs[1])
+# rwR(sub)
+
+# tilde?
+R1 = @rule Δ(~~x::(x->isForm1(x))) => ★(d(★(d(~x))))
+
+@macroexpand @rule Δ(~x::isForm1) => "Success"
+
+# pulling out the subexpression
+rewriter = SymbolicUtils.Fixpoint(SymbolicUtils.Prewalk(SymbolicUtils.Chain(r)))
+
 
-rewriter = SymbolicUtils.Fixpoint(SymbolicUtils.Prewalk(test_rule))
 
 res_exprs =  apply_rewrites(heat_exprs, rewriter)
+sub_exprs =  apply_rewrites([sub], rewriter)
 
 optm_dd_0 = @rule d(d(~x)) => 0
 star_0 = @rule ★(0) => 0