Base.show(model) calling print on Jupyter

[bbrunaud]

Hello

Whenever a model is defined in Jupyter, the output is the full printout of the model, which can be annoying (many many lines of output). Is this the intended behavior?.

regards

Braulio

[mlubin]

If something is annoying, we're likely to accept a PR fixing it.

[odow]

Ref #1180

[odow]

This is going to take some refactoring, because the issue is that we have a mix of print and show, a summary, a plain text model, and a LaTeX model.

In the REPL, Julia> model calls

JuMP.jl/src/print.jl

Lines 152 to 161 in a171d75

	# An `AbstractModel` subtype should implement `show_objective_function_summary`,
	# `show_constraints_summary` and `show_backend_summary` for this method to work.
	function Base.show(io::IO, model::AbstractModel)
	println(io, "A JuMP Model")
	sense = objective_sense(model)
	if sense == MOI.MAX_SENSE
	print(io, "Maximization")
	elseif sense == MOI.MIN_SENSE
	print(io, "Minimization")
	else

but in IJulia/Documenter, ending a cell with model calls

JuMP.jl/src/print.jl

Lines 195 to 197 in a171d75

	function Base.show(io::IO, ::MIME"text/latex", model::AbstractModel)
	print(io, _wrap_in_math_mode(model_string(IJuliaMode, model)))
	end

but calling print(model) calls:

JuMP.jl/src/print.jl

Lines 192 to 194 in a171d75

	function Base.print(io::IO, model::AbstractModel)
	print(io, model_string(REPLMode, model))
	end

To bring some sanity, I'd propose

• Julia> model or ending a cell with model prints the summary
• print(model) prints the model with all constraints in plain-text
• print(model; latex = true) prints the latex version of the model
  • In IJulia and documenter, this pretty prints in MathJax.
  • In the REPL, this prints a string that can be copy-pasted into a tex file.

The only breaking change for this from a user-perspective is that models in IJulia would show a summary by default, and you'd have to use print(model; latex = true) to get the latex version.

Proof-of-concept

struct Model end

function _print_summary(io::IO, model::Model)
    print(io, "model summary")
end

function _print_model(io::IO, model::Model)
    print(io, "full model")
end

function _print_latex(io::IO, model::Model)
    print(io, "\$\$\\min Model + latex\$\$")
end


Base.show(io::IO, model::Model) = _print_summary(io, model)

struct LaTeXModel{T}
    model::T
end

function Base.show(io::IO, model::LaTeXModel)
    return print(io, sprint(_print_latex, model.model))
end

function Base.show(io::IO, ::MIME"text/latex", model::LaTeXModel)
    _print_latex(io, model.model)
end

function Base.print(io::IO, model::Model; latex::Bool = false)
    if latex
        return LaTeXModel(model)
    else
        _print_model(io, model)
    end
end

Base.print(model::Model; latex::Bool = false) = print(stdout, model; latex=latex)

Output from IJulia

Output from the REPL