Merge pull request #179 from TotalVerb/fw/code-simplify

Simplify code thanks to migration from v0.4

REQUIRE

@@ -1,2 +1,2 @@
 julia 0.4
-Compat 0.11.0
+Compat 0.15.0

docs/messages.md

@@ -78,7 +78,7 @@ Every error code starts with letter for the severity `E`:`ERROR`, `W`:`WARN` or
 | E421   | (no longer used)
 | E422   | string uses * to concatenate
 | E423   | named keyword argument must have a default
-| E424   | nested vect is treated as a 1-dimensional array. Use [a;b] instead
+| E424   | (no longer used)
 | E425   | use lintpragma macro inside type declaration
 | E431   | use of length() in a Boolean context, use isempty()
 | E432   | though valid in 0.4, use x() instead of y()
@@ -105,7 +105,7 @@ Every error code starts with letter for the severity `E`:`ERROR`, `W`:`WARN` or
 | E534   | introducing a new name for an implicit argument to the function, use {T<:X}
 | E535   | introducing a new name for an algebric data type, use {T<:X}
 | E536   | use {T<:...} instead of a known type
-| E537   | String constructor does not exist in v0.4; use string() instead
+| E537   | (removed)
 | E538   | known type in parametric data type, use {T<:...}
 |        |
 | **E6** | *Structure Error*

src/Lint.jl

@@ -4,6 +4,13 @@ module Lint
 
 using Base.Meta
 using Compat
+using Compat.TypeUtils
+
+if isdefined(Base, :unwrap_unionall)
+    using Base: unwrap_unionall
+else
+    unwrap_unionall(x) = x
+end
 
 export LintMessage, LintContext, LintStack
 export lintfile, lintstr, lintpkg, lintserver, @lintpragma
@@ -267,10 +274,6 @@ function lintexpr(ex::Expr, ctx::LintContext)
         lintref(ex, ctx)
     elseif ex.head == :typed_vcat# it could be a ref a[b], or an array Int[1,2]
         linttyped_vcat(ex, ctx)
-    elseif ex.head == :dict # homogeneous dictionary
-        lintdict(ex, ctx; typed=false)
-    elseif ex.head == :typed_dict # mixed type dictionary
-        lintdict(ex, ctx; typed=true)
     elseif ex.head == :vcat
         lintvcat(ex, ctx)
     elseif ex.head == :vect # 0.4

src/dict.jl

@@ -1,32 +1,27 @@
-function lintdict(::Expr, ::LintContext; typed::Bool = false)
-    @lintpragma "Ignore unused typed"
-    # TODO: Complain about v0.4-style [a => b for x in y] Dict comprehensions,
-    # deprecated in v0.5.
-end
-
-function lintdict4(ex::Expr, ctx::LintContext)
+function lintdict(ex::Expr, ctx::LintContext)
     typed = isexpr(ex.args[1], :curly)
-    st = 2
     ks = Set{Any}()
     ktypes = Set{Any}()
     vtypes = Set{Any}()
-    for i in st:length(ex.args)
-        a = ex.args[i]
-        if typeof(a) == Expr && a.head == :(=>)
-            if typeof(a.args[1]) != Expr
-                if in(a.args[1], ks)
-                    msg(ctx, :E334, a.args[1], "duplicate key in Dict")
+    for a in ex.args[2:end]
+        if ispairexpr(a)
+            keyexpr = lexicalfirst(a)
+            lit = lexicalvalue(keyexpr)
+            if !isnull(lit)
+                if keyexpr in ks
+                    msg(ctx, :E334, keyexpr, "duplicate key in Dict")
                 end
-                push!(ks, a.args[1])
+                push!(ks, keyexpr)
             end
-            for (j,s) in [(1,ktypes), (2,vtypes)]
-                if typeof(a.args[j]) <: QuoteNode && typeof(a.args[j].value) <: Symbol
-                    push!(s, Symbol)
-                elseif typeof(a.args[j]) <: Number || typeof(a.args[j]) <: AbstractString
-                    push!(s, typeof(a.args[j]))
+            for (j,s) in [(lexicalfirst,ktypes), (lexicallast,vtypes)]
+                kvexpr = j(a)
+                typeguess = lexicaltypeof(kvexpr)
+                if isleaftype(typeguess)
+                    push!(s, typeguess)
+                elseif isexpr(kvexpr, :call) && in(kvexpr.args[1], [:Date, :DateTime])
+                    # TODO: use the existing guesstype infrastructure
                     # we want to add more immutable types such as Date, DateTime, etc.
-                elseif isexpr(a.args[j], :call) && in(a.args[j].args[1], [:Date, :DateTime])
-                    push!(s, a.args[j].args[1])
+                    push!(s, kvexpr.args[1])
                 else
                     if typed
                         push!(s, Any)

src/exprutils.jl

@@ -2,7 +2,17 @@ module ExpressionUtils
 
 using Base.Meta
 
-export split_comparison, simplify_literal
+export split_comparison, simplify_literal, ispairexpr, isliteral,
+       lexicaltypeof, lexicalfirst, lexicallast, lexicalvalue
+
+# TODO: remove when 0.5 support dropped
+function BROADCAST(f, x::Nullable)
+    if isnull(x)
+        Nullable()
+    else
+        Nullable(f(get(x)))
+    end
+end
 
 """
     split_comparison(::Expr)
@@ -44,4 +54,67 @@ function simplify_literal(ex)
     end
 end
 
+"""
+Return `true` if `x` is an expression of the form `:(k => v)`.  Note that on
+v0.5, this is `Expr(:(=>), ...)`, whereas on v0.6 it is `Expr(:call, :(=>),
+...)`.
+"""
+ispairexpr(x) = isexpr(x, :(=>)) || isexpr(x, :call) && x.args[1] == :(=>)
+
+"""
+Return the first entry of the given pair expression, determined lexically.
+Note that on v0.5, this is the first argument of the expression, whereas on
+v0.6, this is the second argument of the expression.
+"""
+lexicalfirst(x) = VERSION < v"0.6-" ? x.args[1] : x.args[2]
+
+"""
+Return the last entry of the given pair expression, determined lexically.  Note
+that on v0.5, this is the second argument of the expression, whereas on v0.6,
+this is the third argument of the expression.
+"""
+lexicallast(x) = VERSION < v"0.6-" ? x.args[2] : x.args[3]
+
+"""
+Return `true` if the value represented by expression `x` is exactly `x` itself;
+that is, `x` is not `Expr`, `QuoteNode`, or `Symbol`.
+"""
+isliteral(x) = !isa(x, Expr) && !isa(x, QuoteNode) && !isa(x, Symbol)
+
+"""
+    lexicalvalue(x) :: Nullable{Any}
+
+If `x` is a literal, or a quoted literal, return that literal wrapped in a
+`Nullable`. Otherwise, return `Nullable{Any}()`.
+"""
+function lexicalvalue(x)
+    if isliteral(x)
+        Nullable{Any}(x)
+    elseif isexpr(x, :quote)
+        if isexpr(x.args[1], :($))
+            lexicalvalue(x.args[1].args[1])
+        else
+            Nullable{Any}(x.args[1])
+        end
+    elseif isa(x, QuoteNode)
+        Nullable{Any}(x.value)
+    else
+        Nullable{Any}()
+    end
+end
+
+"""
+Return the most specific known lexical type of the given expression. Lexical
+type is defined as
+
+- If the expression is a literal, the type of that literal;
+- If the expression is a `QuoteNode`, or an `Expr(:quote, ...)`, the type of
+  whatever is quoted;
+- Otherwise, `Any`.
+
+That is, the maximal amount of information detectable from the lexical context
+alone.
+"""
+lexicaltypeof(x) = get(BROADCAST(typeof, lexicalvalue(x)), Any)
+
 end

src/functions.jl

@@ -4,22 +4,7 @@ const commoncollmethods = Dict{Symbol, Set{Type}}()
 
 # deprecation of specialized version of constructors
 const deprecated_constructors =
-    Dict(:symbol  => :Symbol,
-         :uint    => :UInt,
-         :uint8   => :UInt8,
-         :uint16  => :UInt16,
-         :uint32  => :UInt32,
-         :uint64  => :UInt64,
-         :uint128 => :UInt128,
-         :float16 => :Float16,
-         :float32 => :Float32,
-         :float64 => :Float64,
-         :int     => :Int,
-         :int8    => :Int8,
-         :int16   => :Int16,
-         :int32   => :Int32,
-         :int64   => :Int64,
-         :int128  => :Int128)
+    Dict(:symbol => :Symbol)
 
 const not_constructible = Set([:Union, :Tuple, :Type])
 
@@ -122,8 +107,8 @@ function lintfunction(ex::Expr, ctx::LintContext; ctorType = Symbol(""), isstage
                     msg(ctx, :E536, temptype, "use {T<:...} instead of a known type")
                 end
                 if in(typeconstraint, knowntypes)
-                    dt = eval(typeconstraint)
-                    if isa(dt, Type) && isleaftype(dt)
+                    dt = parsetype(typeconstraint)
+                    if isleaftype(dt)
                         msg(ctx, :E513, adt, "leaf type as a type constraint makes no sense")
                     end
                 end
@@ -267,13 +252,11 @@ function lintfunction(ex::Expr, ctx::LintContext; ctorType = Symbol(""), isstage
         try
             vi = stacktop.localarguments[end][s]
             if haskey(assertions, s)
-                dt = eval(assertions[s])
-                if isa(dt, Type)
-                    vi.typeactual = dt
-                    if dt != Any && haskey(typeRHShints, s) && typeRHShints[s] != Any &&
-                        !(typeRHShints[s] <: dt)
-                        msg(ctx, :E516, s, "type assertion and default seem inconsistent")
-                    end
+                dt = parsetype(assertions[s])
+                vi.typeactual = dt
+                if dt != Any && haskey(typeRHShints, s) && typeRHShints[s] != Any &&
+                    !(typeRHShints[s] <: dt)
+                    msg(ctx, :E516, s, "type assertion and default seem inconsistent")
                 end
             elseif haskey(typeRHShints, s)
                 vi.typeactual = typeRHShints[s]
@@ -390,6 +373,7 @@ function lintfunctioncall(ex::Expr, ctx::LintContext; inthrow::Bool=false)
         else
             inclfile = ""
             try
+                # TODO: not a good idea...
                 inclfile = eval(ex.args[2])
             catch
                 inclfile = string(ex.args[2])
@@ -414,7 +398,7 @@ function lintfunctioncall(ex::Expr, ctx::LintContext; inthrow::Bool=false)
         end
 
         if ex.args[1] == :Dict || isexpr(ex.args[1], :curly) && ex.args[1].args[1] == :Dict
-            lintdict4(ex, ctx)
+            lintdict(ex, ctx)
             return
         end
         known=false
@@ -429,10 +413,7 @@ function lintfunctioncall(ex::Expr, ctx::LintContext; inthrow::Bool=false)
             end
             msg(ctx, :I481, ex.args[1], "replace $(ex.args[1])() with $(repl)()$(suffix)")
         end
-        if VERSION < v"0.5-" && ex.args[1] == :String
-            msg(ctx, :E537, ex.args[1],
-                "String constructor does not exist in v0.4; use string() instead")
-        elseif ex.args[1] in not_constructible
+        if ex.args[1] in not_constructible
             msg(ctx, :W441, "type $(ex.args[1]) is not constructible like this")
         elseif ex.args[1] == :(+)
             lintplus(ex, ctx)
@@ -518,8 +499,8 @@ function lintfunctioncall(ex::Expr, ctx::LintContext; inthrow::Bool=false)
             s = lowercase(string(ex.args[1]))
             if contains(s,"error") || contains(s,"exception") || contains(s,"mismatch") || contains(s,"fault")
                 try
-                    dt = eval(ex.args[1])
-                    if isa(dt, Type) && dt <: Exception && !pragmaexists( "Ignore unthrown " * string(ex.args[1]), ctx)
+                    dt = parsetype(ex.args[1])
+                    if dt <: Exception && !pragmaexists( "Ignore unthrown " * string(ex.args[1]), ctx)
                         msg(ctx, :W448, string(ex.args[1]) * " is an Exception but it is not enclosed in a throw()")
                     end
                 end
@@ -536,9 +517,9 @@ function lintfunctioncall(ex::Expr, ctx::LintContext; inthrow::Bool=false)
                     for kw in ex.args[i].args
                         if isexpr(kw, :(...))
                             lintexpr(kw.args[1], ctx)
-                        elseif isexpr(kw, :(=>))
-                            lintexpr(kw.args[1], ctx)
-                            lintexpr(kw.args[2], ctx)
+                        elseif ispairexpr(kw)
+                            lintexpr(lexicalfirst(kw), ctx)
+                            lintexpr(lexicallast(kw), ctx)
                         elseif isa(kw, Expr) && length(kw.args) == 2
                             lintexpr(kw.args[2], ctx)
                         elseif isa(kw, Symbol)