Change sentinel in find(first|next|prev|last) to nothing

base/array.jl

@@ -1495,7 +1495,7 @@ cat(n::Integer, x::Integer...) = reshape([x...], (ntuple(x->1, n-1)..., length(x
 """
  findnext(A, i::Integer)
 
-Find the next linear index >= `i` of a `true` element of `A`, or `0` if not found.
+Find the next linear index >= `i` of a `true` element of `A`, or `nothing` if not found.
 
 # Examples
 ```jldoctest
@@ -1508,7 +1508,6 @@ julia> findnext(A, 1)
 2
 
 julia> findnext(A, 3)
-0
 ```
 """
 function findnext(A, start::Integer)
@@ -1526,14 +1525,14 @@ function findnext(A, start::Integer)
  end
  i = nextind(A, i)
  end
- return 0
+ return nothing
 end
 
 """
  findfirst(A)
 
 Return the linear index of the first `true` value in `A`.
-Return `0` if no such value is found.
+Return `nothing` if no such value is found.
 To search for other kinds of values, pass a predicate as the first argument.
 
 # Examples
@@ -1546,16 +1545,17 @@ julia> A = [false false; true false]
 julia> findfirst(A)
 2
 
-julia> findfirst(falses(3))
-0
+julia> findfirst(falses(3)) == nothing
+true
 ```
 """
 findfirst(A) = findnext(A, 1)
 
 """
  findnext(predicate::Function, A, i::Integer)
 
-Find the next linear index >= `i` of an element of `A` for which `predicate` returns `true`, or `0` if not found.
+Find the next linear index >= `i` of an element of `A` for which `predicate` returns `true`,
+or `nothing` if not found.
 
 # Examples
 ```jldoctest
@@ -1567,8 +1567,8 @@ julia> A = [1 4; 2 2]
 julia> findnext(isodd, A, 1)
 1
 
-julia> findnext(isodd, A, 2)
-0
+julia> findnext(isodd, A, 2) == nothing
+true
 ```
 """
 function findnext(testf::Function, A, start::Integer)
@@ -1580,14 +1580,14 @@ function findnext(testf::Function, A, start::Integer)
  end
  i = nextind(A, i)
  end
- return 0
+ return nothing
 end
 
 """
  findfirst(predicate::Function, A)
 
 Return the linear index of the first element of `A` for which `predicate` returns `true`.
-Return `0` if there is no such element.
+Return `nothing` if there is no such element.
 
 # Examples
 ```jldoctest
@@ -1599,8 +1599,8 @@ julia> A = [1 4; 2 2]
 julia> findfirst(iseven, A)
 2
 
-julia> findfirst(x -> x>10, A)
-0
+julia> findfirst(x -> x>10, A) == nothing
+true
 
 julia> findfirst(equalto(4), A)
 3
@@ -1611,7 +1611,7 @@ findfirst(testf::Function, A) = findnext(testf, A, 1)
 """
  findprev(A, i::Integer)
 
-Find the previous linear index <= `i` of a `true` element of `A`, or `0` if not found.
+Find the previous linear index <= `i` of a `true` element of `A`, or `nothing` if not found.
 
 # Examples
 ```jldoctest
@@ -1623,8 +1623,8 @@ julia> A = [false false; true true]
 julia> findprev(A,2)
 2
 
-julia> findprev(A,1)
-0
+julia> findprev(A,1) == nothing
+true
 ```
 """
 function findprev(A, start::Integer)
@@ -1639,14 +1639,14 @@ function findprev(A, start::Integer)
  a != 0 && return i
  i = prevind(A, i)
  end
- return 0
+ return nothing
 end
 
 """
  findlast(A)
 
 Return the linear index of the last `true` value in `A`.
-Return `0` if there is no `true` value in `A`.
+Return `nothing` if there is no `true` value in `A`.
 
 # Examples
 ```jldoctest
@@ -1660,8 +1660,8 @@ julia> findlast(A)
 
 julia> A = falses(2,2);
 
-julia> findlast(A)
-0
+julia> findlast(A) == nothing
+true
 ```
 """
 findlast(A) = findprev(A, endof(A))
@@ -1670,7 +1670,7 @@ findlast(A) = findprev(A, endof(A))
  findprev(predicate::Function, A, i::Integer)
 
 Find the previous linear index <= `i` of an element of `A` for which `predicate` returns `true`, or
-`0` if not found.
+`nothing` if not found.
 
 # Examples
 ```jldoctest
@@ -1679,8 +1679,8 @@ julia> A = [4 6; 1 2]
  4 6
  1 2
 
-julia> findprev(isodd, A, 1)
-0
+julia> findprev(isodd, A, 1) == nothing
+true
 
 julia> findprev(isodd, A, 3)
 2
@@ -1692,14 +1692,14 @@ function findprev(testf::Function, A, start::Integer)
  testf(A[i]) && return i
  i = prevind(A, i)
  end
- return 0
+ return nothing
 end
 
 """
  findlast(predicate::Function, A)
 
 Return the linear index of the last element of `A` for which `predicate` returns `true`.
-Return `0` if there is no such element.
+Return `nothing` if there is no such element.
 
 # Examples
 ```jldoctest
@@ -1711,8 +1711,8 @@ julia> A = [1 2; 3 4]
 julia> findlast(isodd, A)
 2
 
-julia> findlast(x -> x > 5, A)
-0
+julia> findlast(x -> x > 5, A) == nothing
+true
 ```
 """
 findlast(testf::Function, A) = findprev(testf, A, endof(A))

base/bitarray.jl

@@ -1459,13 +1459,13 @@ function unsafe_bitfindnext(Bc::Vector{UInt64}, start::Integer)
  end
  end
  end
- return 0
+ return nothing
 end
 
-# returns the index of the next non-zero element, or 0 if all zeros
+# returns the index of the next true element, or nothing if all false
 function findnext(B::BitArray, start::Integer)
  start > 0 || throw(BoundsError(B, start))
- start > length(B) && return 0
+ start > length(B) && return nothing
  unsafe_bitfindnext(B.chunks, start)
 end
 
@@ -1474,11 +1474,11 @@ end
 # aux function: same as findnext(~B, start), but performed without temporaries
 function findnextnot(B::BitArray, start::Integer)
  start > 0 || throw(BoundsError(B, start))
- start > length(B) && return 0
+ start > length(B) && return nothing
 
  Bc = B.chunks
  l = length(Bc)
- l == 0 && return 0
+ l == 0 && return nothing
 
  chunk_start = _div64(start-1)+1
  within_chunk_start = _mod64(start-1)
@@ -1499,7 +1499,7 @@ function findnextnot(B::BitArray, start::Integer)
  elseif Bc[l] | mask != _msk_end(B)
  return (l-1) << 6 + trailing_ones(Bc[l] | mask) + 1
  end
- return 0
+ return nothing
 end
 findfirstnot(B::BitArray) = findnextnot(B,1)
 
@@ -1508,7 +1508,7 @@ function findnext(pred::EqualTo, B::BitArray, start::Integer)
  v = pred.x
  v == false && return findnextnot(B, start)
  v == true && return findnext(B, start)
- return 0
+ return nothing
 end
 #findfirst(B::BitArray, v) = findnext(B, 1, v) ## defined in array.jl
 
@@ -1520,9 +1520,9 @@ function findnext(testf::Function, B::BitArray, start::Integer)
  f0 && !f1 && return findnextnot(B, start)
 
  start > 0 || throw(BoundsError(B, start))
- start > length(B) && return 0
+ start > length(B) && return nothing
  f0 && f1 && return Int(start)
- return 0 # last case: !f0 && !f1
+ return nothing # last case: !f0 && !f1
 end
 #findfirst(testf::Function, B::BitArray) = findnext(testf, B, 1) ## defined in array.jl
 
@@ -1541,18 +1541,18 @@ function unsafe_bitfindprev(Bc::Vector{UInt64}, start::Integer)
  end
  end
  end
- return 0
+ return nothing
 end
 
-# returns the index of the previous non-zero element, or 0 if all zeros
+# returns the index of the previous true element, or nothing if all false
 function findprev(B::BitArray, start::Integer)
- start > 0 || return 0
+ start > 0 || return nothing
  start > length(B) && throw(BoundsError(B, start))
  unsafe_bitfindprev(B.chunks, start)
 end
 
 function findprevnot(B::BitArray, start::Integer)
- start > 0 || return 0
+ start > 0 || return nothing
  start > length(B) && throw(BoundsError(B, start))
 
  Bc = B.chunks
@@ -1571,7 +1571,7 @@ function findprevnot(B::BitArray, start::Integer)
  end
  end
  end
- return 0
+ return nothing
 end
 findlastnot(B::BitArray) = findprevnot(B, length(B))
 
@@ -1580,7 +1580,7 @@ function findprev(pred::EqualTo, B::BitArray, start::Integer)
  v = pred.x
  v == false && return findprevnot(B, start)
  v == true && return findprev(B, start)
- return 0
+ return nothing
 end
 #findlast(B::BitArray, v) = findprev(B, 1, v) ## defined in array.jl
 
@@ -1591,10 +1591,10 @@ function findprev(testf::Function, B::BitArray, start::Integer)
  !f0 && f1 && return findprev(B, start)
  f0 && !f1 && return findprevnot(B, start)
 
- start > 0 || return 0
+ start > 0 || return nothing
  start > length(B) && throw(BoundsError(B, start))
  f0 && f1 && return Int(start)
- return 0 # last case: !f0 && !f1
+ return nothing # last case: !f0 && !f1
 end
 #findlast(testf::Function, B::BitArray) = findprev(testf, B, 1) ## defined in array.jl
 

base/bitset.jl

@@ -68,14 +68,16 @@ function _bits_findnext(b::Bits, start::Int)
  # start is 0-based
  # @assert start >= 0
  _div64(start) + 1 > length(b) && return -1
- unsafe_bitfindnext(b, start+1) - 1
+ ind = unsafe_bitfindnext(b, start+1)
+ ind === nothing ? -1 : ind - 1
 end
 
 function _bits_findprev(b::Bits, start::Int)
  # start is 0-based
  # @assert start <= 64 * length(b) - 1
  start >= 0 || return -1
- unsafe_bitfindprev(b, start+1) - 1
+ ind = unsafe_bitfindprev(b, start+1)
+ ind === nothing ? -1 : ind - 1
 end
 
 # An internal function for setting the inclusion bit for a given integer

base/client.jl

@@ -149,7 +149,7 @@ function display_error(io::IO, er, bt)
  print_with_color(Base.error_color(), io, "ERROR: "; bold = true)
  # remove REPL-related frames from interactive printing
  eval_ind = findlast(addr->Base.REPL.ip_matches_func(addr, :eval), bt)
- if eval_ind != 0
+ if eval_ind !== nothing
  bt = bt[1:eval_ind-1]
  end
  showerror(IOContext(io, :limit => true), er, bt)

base/combinatorics.jl

@@ -75,7 +75,7 @@ function permute!!(a, p::AbstractVector{<:Integer})
  count = 0
  start = 0
  while count < length(a)
- ptr = start = findnext(!iszero, p, start+1)
+ ptr = start = findnext(!iszero, p, start+1)::Int
  temp = a[start]
  next = p[start]
  count += 1
@@ -125,7 +125,7 @@ function invpermute!!(a, p::AbstractVector{<:Integer})
  count = 0
  start = 0
  while count < length(a)
- start = findnext(!iszero, p, start+1)
+ start = findnext(!iszero, p, start+1)::Int
  temp = a[start]
  next = p[start]
  count += 1

base/event.jl

@@ -231,7 +231,7 @@ function ensure_rescheduled(othertask::Task)
  # also need to return it to the runnable state
  # before throwing an error
  i = findfirst(t->t===ct, Workqueue)
- i == 0 || deleteat!(Workqueue, i)
+ i === nothing || deleteat!(Workqueue, i)
  ct.state = :runnable
  end
  nothing

base/file.jl

@@ -271,7 +271,7 @@ function tempname(temppath::AbstractString,uunique::UInt32)
  tempp = cwstring(temppath)
  tname = Vector{UInt16}(uninitialized, 32767)
  uunique = ccall(:GetTempFileNameW,stdcall,UInt32,(Ptr{UInt16},Ptr{UInt16},UInt32,Ptr{UInt16}), tempp,temp_prefix,uunique,tname)
- lentname = findfirst(iszero,tname)-1
+ lentname = coalesce(findfirst(iszero,tname), 0)-1
  if uunique == 0 || lentname <= 0
  error("GetTempFileName failed: $(Libc.FormatMessage())")
  end

base/filesystem.jl

@@ -43,6 +43,7 @@ import Base:
  nb_available, position, read, read!, readavailable, seek, seekend, show,
  skip, stat, unsafe_read, unsafe_write, transcode, uv_error, uvhandle,
  uvtype, write
+using Base: coalesce
 
 if Sys.iswindows()
  import Base: cwstring

base/inference.jl

@@ -1822,7 +1822,7 @@ function builtin_tfunction(@nospecialize(f), argtypes::Array{Any,1},
  tf = t_ifunc[iidx]
  else
  fidx = findfirst(x->x===f, t_ffunc_key)
- if fidx == 0
+ if fidx === nothing
  # unknown/unhandled builtin function
  return Any
  end
@@ -5147,7 +5147,7 @@ function statement_cost(ex::Expr, line::Int, src::CodeInfo, mod::Module, params:
  return plus_saturate(argcost, isknowntype(ex.typ) ? 4 : params.inline_nonleaf_penalty)
  end
  fidx = findfirst(x->x===f, t_ffunc_key)
- if fidx == 0
+ if fidx === nothing
  # unknown/unhandled builtin or anonymous function
  # Use the generic cost of a direct function call
  return plus_saturate(argcost, 20)