[WIP] Implementation of write_to_file that use MathOptFormat.

Project.toml

@@ -8,6 +8,7 @@ Calculus = "49dc2e85-a5d0-5ad3-a950-438e2897f1b9"
 DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+MathOptFormat = "f4570300-c277-12e8-125c-4912f86ce65d"
 MathOptInterface = "b8f27783-ece8-5eb3-8dc8-9495eed66fee"
 NaNMath = "77ba4419-2d1f-58cd-9bb1-8ffee604a2e3"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
@@ -18,6 +19,7 @@ Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 Calculus = "0.5"
 DataStructures = "0.17"
 ForwardDiff = "~0.5.0, ~0.6, ~0.7, ~0.8, ~0.9, ~0.10"
+MathOptFormat = "≥ 0.2"
 MathOptInterface = "~0.9.1"
 NaNMath = "0.3"
 OffsetArrays = "≥ 0.2.13"

src/JuMP.jl

@@ -16,6 +16,7 @@ using SparseArrays
 import MathOptInterface
 const MOI = MathOptInterface
 const MOIU = MOI.Utilities
+using MathOptFormat
 
 import Calculus
 import DataStructures.OrderedDict
@@ -38,8 +39,8 @@ Base.@deprecate(setlowerbound,     JuMP.set_lower_bound)
 Base.@deprecate(setupperbound,     JuMP.set_upper_bound)
 Base.@deprecate(linearterms,       JuMP.linear_terms)
 
-writeLP(args...; kargs...) = error("writeLP has been removed from JuMP. Use `MathOptFormat.jl` instead.")
-writeMPS(args...; kargs...) = error("writeMPS has been removed from JuMP. Use `MathOptFormat.jl` instead.")
+writeLP(args...; kargs...) = error("writeLP has been merged into write_to_file and its arguments have changed.")
+writeMPS(args...; kargs...) = error("writeMPS has been merged into write_to_file and its arguments have changed.")
 
 include("utils.jl")
 
@@ -787,6 +788,7 @@ include("nlp.jl")
 include("print.jl")
 include("lp_sensitivity.jl")
 include("callbacks.jl")
+include("file_formats.jl")
 
 # JuMP exports everything except internal symbols, which are defined as those
 # whose name starts with an underscore. If you don't want all of these symbols

src/file_formats.jl

@@ -0,0 +1,28 @@
+function write_to_file(model::Model, io::IO, format::MathOptFormat.FileFormat; kwargs...)
+    @assert format != AUTOMATIC_FILE_FORMAT
+    dest = MathOptFormat._file_formats[format][2]()
+    MOI.copy_to(dest, backend(model))
+    MOI.write_to_file(dest, io)
+    return
+end
+
+"""
+    write_to_file(model::Model, filename::String; format::FileFormat=AUTOMATIC_FILE_FORMAT, compression::MathOptFormat.AbstractCompressionScheme=MathOptFormat.AutomaticCompression(), kwargs...)
+
+Write `model` to the file called `filename` using the format `format`.
+
+Valid formats are given by the enum [`FileFormat`](@ref). Valid compression algorithms
+are given by a concrete subtype of [`AbstractCompressionScheme`](@ref).
+
+For keyword options, see [MathOptFormat.jl](https://github.com/odow/MathOptFormat.jl).
+"""
+function write_to_file(model::Model, filename::String;
+                       format::MathOptFormat.FileFormat=MathOptFormat.AUTOMATIC_FILE_FORMAT,
+                       compression::MathOptFormat.AbstractCompressionScheme=MathOptFormat.AutomaticCompression(),
+                       kwargs...)
+    if format == AUTOMATIC_FILE_FORMAT
+        format = MathOptFormat._filename_to_format(filename)
+    end
+    MOI.write_to_file(model, filename, compression=compression)
+    return
+end