Fix printing of binary operators with 1 arg

[MasonProtter]

Before this fix:

julia> SymbolicUtils.show_call(stdout, (-), 1)
1

After this fix:

julia> SymbolicUtils.show_call(stdout, (-), 1)
-(1)

[codecov-commenter]

Codecov Report

Merging #375 (c88d3df) into master (48cc5ff) will decrease coverage by 0.33%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #375      +/-   ##
==========================================
- Coverage   83.70%   83.36%   -0.34%     
==========================================
  Files          12       12              
  Lines        1479     1479              
==========================================
- Hits         1238     1233       -5     
- Misses        241      246       +5     

Impacted Files	Coverage Δ
src/types.jl	84.99% <100.00%> (ø)
src/polyform.jl	92.76% <0.00%> (-1.36%)	:arrow_down:
src/ordering.jl	89.53% <0.00%> (-1.17%)	:arrow_down:
src/code.jl	80.55% <0.00%> (-0.56%)	:arrow_down:

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[MasonProtter]

Hm, this seems to have somehow broken the printing of more complicated expressions for me, etc.

julia> 1 + -1*σ1
1 - (-((-σ1)^1))

:(

Still not great, but way better than before (its at least mathematically correct). This is just happening because of the way the printing is assuming constructor level simplification.

---

using SymbolicUtils
using SymbolicUtils.Rewriters
using SymbolicUtils: Sym, Term, Symbolic, sym_isa
SymbolicUtils.show_simplified[] = false

struct Clifford end

@syms σ1::Clifford

for op ∈ (:*, :+, :-, :^, :/)
    @eval begin
        Base.$op(x::Symbolic{Clifford}, y::Symbolic{Clifford}) = Term{Clifford}($op, [x, y])
        Base.$op(x, y::Symbolic{Clifford}) = Term{Clifford}($op, [x, y])
        Base.$op(x::Symbolic{Clifford}, y) = Term{Clifford}($op, [x, y])

        Base.$op(x::Number, y::Symbolic{Clifford}) = Term{Clifford}($op, [x, y])
        Base.$op(x::Symbolic{Clifford}, y::Number) = Term{Clifford}($op, [x, y])
    end
end

[shashi]

Seems to have gotten fixed over time.