From 3a3b69eb9dde9da3adad8bd7865996813a2021b0 Mon Sep 17 00:00:00 2001
From: Katharine Hyatt <67932820+kshyatt-aws@users.noreply.github.com>
Date: Wed, 27 Nov 2024 15:33:50 +0100
Subject: [PATCH] Even more small cleanups (#22)

* Case mini cleanup

* Small cleanup for gphase
---
 src/visitor.jl | 31 ++++++++++++++-----------------
 1 file changed, 14 insertions(+), 17 deletions(-)

diff --git a/src/visitor.jl b/src/visitor.jl
index aa2c7fa..46e1714 100644
--- a/src/visitor.jl
+++ b/src/visitor.jl
@@ -370,7 +370,6 @@ function handle_gate_modifiers(ixs, mods::Vector{QasmExpression}, control_qubits
         if head(mod) ∈ (:negctrl, :ctrl)
             control_qubit = pop!(control_qubits)
             for (ii, ix) in enumerate(ixs)
-                exp      = ix.exponent
                 targets  = ix.targets
                 controls = ix.controls
                 bit = head(mod) == :ctrl ? 1 : 0
@@ -378,7 +377,7 @@ function handle_gate_modifiers(ixs, mods::Vector{QasmExpression}, control_qubits
                 if !is_gphase
                     targets  = pushfirst!(targets, control_qubit)
                 end
-                ixs[ii] = (type=ix.type, arguments=ix.arguments, targets=targets, controls=controls, exponent=exp)
+                ixs[ii] = (type=ix.type, arguments=ix.arguments, targets=targets, controls=controls, exponent=ix.exponent)
             end
         elseif head(mod) == :inv
             reverse!(ixs)
@@ -400,9 +399,9 @@ function handle_gate_modifiers(ixs, mods::Vector{QasmExpression}, control_qubits
 end
 
 function splat_gate_targets(gate_targets::Vector{Vector{Int}})
-    target_lengths::Vector{Int} = Int[length(t) for t in gate_targets]
-    longest          = maximum(target_lengths)
-    must_splat::Bool = any(len->len!=1 || len != longest, target_lengths)
+    target_lengths::Vector{Int} = map(length, gate_targets)::Vector{Int}
+    longest                     = maximum(target_lengths)
+    must_splat::Bool            = any(len->len!=1 || len != longest, target_lengths)
     !must_splat && return longest, gate_targets
     for target_ix in filter(ix->target_lengths[ix] == 1, 1:length(gate_targets))
         append!(gate_targets[target_ix], fill(only(gate_targets[target_ix]), longest-1))
@@ -415,11 +414,11 @@ function visit_gphase_call(v::AbstractVisitor, program_expr::QasmExpression)
     n_called_with::Int           = qubit_count(v)
     gate_targets::Vector{Int}    = collect(0:n_called_with-1)
     provided_arg::QasmExpression = only(program_expr.args[2].args)
-    evaled_arg        = v(provided_arg)
-    applied_arguments = CircuitInstruction[(type="gphase", arguments=[evaled_arg], targets=gate_targets, controls=Pair{Int,Int}[], exponent=1.0)]
-    mods::Vector{QasmExpression} = has_modifiers ? program_expr.args[4].args : QasmExpression[]
-    applied_arguments = handle_gate_modifiers(applied_arguments, mods, deepcopy(gate_targets), true)
-    target_mapper     = Dict{Int, Int}(g_ix=>gate_targets[g_ix+1][1] for g_ix in 0:n_called_with-1)
+    evaled_arg                   = v(provided_arg)
+    applied_arguments            = CircuitInstruction[(type="gphase", arguments=[evaled_arg], targets=gate_targets, controls=Pair{Int,Int}[], exponent=1.0)]
+    mods::Vector{QasmExpression} = length(program_expr.args) == 4 ? program_expr.args[4].args : QasmExpression[]
+    applied_arguments            = handle_gate_modifiers(applied_arguments, mods, deepcopy(gate_targets), true)
+    target_mapper                = Dict{Int, Int}(g_ix=>gate_targets[g_ix+1][1] for g_ix in 0:n_called_with-1)
     push!(v, map(ix->remap(ix, target_mapper), applied_arguments))
     return
 end
@@ -601,12 +600,10 @@ function (v::AbstractVisitor)(program_expr::QasmExpression)
         all_cases  = convert(Vector{QasmExpression}, program_expr.args[2:end])
         default    = findfirst(expr->head(expr) == :default, all_cases)
         case_found = false
-        for case in all_cases
-            if head(case) == :case && case_val ∈ v(case.args[1])
-                case_found = true
-                foreach(v, convert(Vector{QasmExpression}, case.args[2:end]))
-                break
-            end
+        for case in filter(case->head(case) == :case && case_val ∈ v(case.args[1]), all_cases)
+            case_found = true
+            foreach(v, convert(Vector{QasmExpression}, case.args[2:end]))
+            break
         end
         if !case_found
             isnothing(default) && throw(QasmVisitorError("no case matched and no default defined."))
@@ -809,7 +806,7 @@ function (v::AbstractVisitor)(program_expr::QasmExpression)
         end
         v.qubit_count += qubit_size
     elseif head(program_expr) ∈ (:power_mod, :inverse_mod, :control_mod, :negctrl_mod)
-        mods = QasmExpression(:modifiers)
+        mods            = QasmExpression(:modifiers)
         mod_expr, inner = evaluate_modifiers(v, program_expr)
         push!(mods, mod_expr)
         while head(inner) != :gate_call # done