From 1a69913e24468657b1264f13feb3eb9ca483fae8 Mon Sep 17 00:00:00 2001
From: David Widmann <dev+github@devmotion.de>
Date: Mon, 23 Jul 2018 01:09:03 +0200
Subject: [PATCH] Replace capture with if

---
 src/MuladdMacro.jl | 73 ++++++++++++++++++++++++++++++++--------------
 1 file changed, 51 insertions(+), 22 deletions(-)

diff --git a/src/MuladdMacro.jl b/src/MuladdMacro.jl
index 41f0d0b..a526dd8 100644
--- a/src/MuladdMacro.jl
+++ b/src/MuladdMacro.jl
@@ -1,6 +1,6 @@
 module MuladdMacro
 
-using MacroTools: postwalk, @capture
+using MacroTools: postwalk
 
 """
     @muladd
@@ -82,28 +82,48 @@ function sub_to_muladd(ex)
     return ex
 end
 
+"""
+    iscall(ex, op)
+
+Determine whether `ex` is a call of operation `op`.
+"""
+iscall(ex::Expr, op) =
+    ex.head == :call && !isempty(ex.args) && ex.args[1] == op
+iscall(ex, op) = false
+
 """
     isdotcall(ex)
 
 Determine whether `ex` is a dot call.
 """
-isdotcall(ex) =
-    (@capture(ex, (f_)(__)) && startswith(string(f), '.')) ||
-    @capture(ex, (_).(__))
+isdotcall(ex::Expr) =
+    (ex.head == :. && length(ex.args) == 2 && Meta.isexpr(ex.args[2], :tuple)) ||
+    (ex.head == :call && !isempty(ex.args) && startswith(string(ex.args[1]), '.'))
+isdotcall(ex) = false
+
+"""
+    isdotcall(ex, op)
+
+Determine whether `ex` is a dot call of operation `op`.
+"""
+isdotcall(ex::Expr, op) =
+    (ex.head == :. && length(ex.args) == 2 && ex.args[1] == op && Meta.isexpr(ex.args[2], :tuple)) ||
+    (ex.head == :call && !isempty(ex.args) && ex.args[1] == Symbol('.', op))
+isdotcall(ex, op) = false
 
 """
     issum(ex)
 
 Determine whether `ex` is a sum.
 """
-issum(ex) = @capture(ex, +(__) | .+(__) | (+).(__))
+issum(ex) = iscall(ex, :+) || isdotcall(ex, :+)
 
 """
     issub(ex)
 
 Determine whether `ex` is a subtraction.
 """
-issub(ex) = @capture(ex, -(_, _) | .-(_, _) | (-).(_, _))
+issub(ex) = iscall(ex, :-) || isdotcall(ex, :-)
 
 """
     ismul(ex, dot::Bool)
@@ -111,13 +131,7 @@ issub(ex) = @capture(ex, -(_, _) | .-(_, _) | (-).(_, _))
 Determine whether expression `ex` is a multiplication that is dotted if
 `dot` is `true` and not dotted otherwise.
 """
-function ismul(ex, dot::Bool)
-    if dot
-        return @capture(ex, .*(__) | (*).(__))
-    else
-        return @capture(ex, *(__))
-    end
-end
+ismul(ex, dot::Bool) = dot ? isdotcall(ex, :*) : iscall(ex, :*)
 
 """
     newmuladd(x, y, z, dot::Bool)
@@ -139,10 +153,16 @@ end
 
 Return arguments of function call in `ex`.
 """
-function args(ex)
-    @capture(ex, (_)(x__) | (_).(x__)) || error("expression is not a function call")
+function args(ex::Expr)
+    if ex.head == :call && length(ex.args) > 1
+        return ex.args[2:end]
+    end
 
-    return x
+    if ex.head == :. && length(ex.args) == 2 && Meta.isexpr(ex.args[2], :tuple) && !isempty(ex.args[2].args)
+        return ex.args[2].args
+    end
+
+    error("expression is not a function call with arguments")
 end
 
 """
@@ -152,7 +172,15 @@ Split arguments of function call `ex` before last argument and combine first
 arguments to one expression if possible.
 """
 function splitargs(ex)
-    @capture(ex, (_)(x__, y_) | (_).(x__, y_)) || error("cannot split arguments")
+    if ex.head == :call && length(ex.args) > 2
+        x = ex.args[2:end-1]
+        y = ex.args[end]
+    elseif ex.head == :. && length(ex.args) == 2 && Meta.isexpr(ex.args[2], :tuple) && length(ex.args[2].args) > 1
+        x = ex.args[2].args[1:end-1]
+        y = ex.args[2].args[end]
+    else
+        error("cannot split arguments")
+    end
 
     return newargs(ex, x...), y
 end
@@ -165,15 +193,16 @@ Create new expression of function call `ex` with arguments `args`.
 Unary function calls are not considered, i.e. if only one function
 argument is provided it is returned.
 """
-function newargs(ex, args...)
+function newargs(ex::Expr, args...)
     # Return single argument
     length(args) == 1 && return args[1]
 
     # Create function calls with new arguments
-    if @capture(ex, (f_)(__))
-        return :($f($(args...)))
-    elseif @capture(ex, (f_).(__))
-        return :(($f).($(args...)))
+    if ex.head == :call && !isempty(ex.args)
+        return Expr(:call, ex.args[1], args...)
+    end
+    if ex.head == :. && length(ex.args) == 2 && Meta.isexpr(ex.args[2], :tuple)
+        return Expr(:., ex.args[1], Expr(:tuple, args...))
     end
 
     error("expression is not a function call")