expand docs

README.md

@@ -6,8 +6,6 @@
 
 This package implements a very small extension to [Bumper.jl](https://github.com/MasonProtter/Bumper.jl). 
 
-### Introduction and Motivation 
-
 A common pattern in our own (the developers') codes is the following: 
 ```julia
 @no_escape begin 
@@ -26,9 +24,9 @@ After writing the same pattern 10 times, we wondered whether there is an easy wa
 end
 ```
 
-### Documentation
+### Preliminary Documentation
 
-For now, there is just a simple example. More soon ... 
+For now, there is are just a few simple use-case examples.
 ```julia
 using WithAlloc, LinearAlgebra, Bumper 
 

src/WithAlloc.jl

@@ -13,6 +13,17 @@ function _bumper_alloc(allocinfo::NTuple{N, <: Tuple}) where {N}
    ntuple(i -> Bumper.alloc!(Bumper.default_buffer(), allocinfo[i]...), N)
 end
 
+macro withalloc1(ex)
+   fncall = esc(ex.args[1])
+   args = esc.(ex.args[2:end])
+   quote
+      let 
+         allocinfo = whatalloc($fncall, $(args...), )
+         storobj = Bumper.alloc!(Bumper.default_buffer(), allocinfo... )
+         $(fncall)(storobj, $(args...), )
+      end
+   end
+end
 
 macro withalloc(ex)
    fncall = esc(ex.args[1])

test/_readme.jl

@@ -41,3 +41,26 @@ end
 using BenchmarkTools 
 @btime alloctest($B, $C)  
 # 125.284 ns (0 allocations: 0 bytes)
+# ------------------------------------------------------------------------
+
+# Multiple arrays is handled via tuples: 
+
+B = randn(5,10)
+C = randn(10, 3)
+D = randn(10, 5)
+A1 = B * C 
+A2 = B * D
+
+mymul2!(A1, A2, B, C, D) = mul!(A1, B, C), mul!(A2, B, D)
+
+function WithAlloc.whatalloc(::typeof(mymul2!), B, C, D) 
+   T1 = promote_type(eltype(B), eltype(C)) 
+   T2 = promote_type(eltype(B), eltype(D))
+   return ( (T1, size(B, 1), size(C, 2)), 
+            (T2, size(B, 1), size(D, 2)) )
+end
+
+@no_escape begin 
+   A1b, A2b = WithAlloc.@withalloc mymul2!(B, C, D)
+   @show A1 ≈ A1b, A2 ≈ A2b   # true, true 
+end