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PrettyPrinting.jl
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PrettyPrinting.jl
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module PrettyPrinting
using ..AbstractAlgebra
import ..AbstractAlgebra: MatrixElem
import ..AbstractAlgebra: NCRingElem
import ..AbstractAlgebra: RingElem
using Preferences: Preferences, @load_preference, @set_preferences!
import Base: displaysize
import Base: get
import Base: getindex
import Base: haskey
import Base: in
import Base: lock
import Base: pipe_reader
import Base: pipe_writer
import Base: print
import Base: show
import Base: unlock
import Base: write
export @enable_all_show_via_expressify
export @show_name
export @show_special
export @show_special_elem
export Dedent
export IOCustom
export Indent
export Lowercase
export LowercaseOff
export allow_unicode
export canonicalize
export expr_to_latex_string
export expr_to_string
export expressify
export extra_name
export get_current_module
export get_html_as_latex
export get_name
export get_syntactic_sign_abs
export indent_string!
export is_syntactic_one
export is_syntactic_zero
export is_terse
export is_unicode_allowed
export obj_to_latex_string
export obj_to_string
export obj_to_string_wrt_times
export pretty
export print_integer_string
export print_obj
export printer
export set_current_module
export set_html_as_latex
export set_name!
export show_obj
export show_via_expressify
export terse
export with_unicode
# printing is done with respect to the following precedences
# There is no point in using the julia values because we add our own ops
const prec_lowest = 0
const prec_inf_Equal = 5 # infix ==
const prec_inf_Plus = 11 # infix a+b+c
const prec_inf_Minus = 11 # infix a-b-c
const prec_inf_Times = 13 # infix a*b*c
const prec_inf_Divide = 13 # infix a/b/c
const prec_inf_DoubleDivide = 14 # infix a//b//c
const prec_inf_CenterDot = 15 # non associative * with spaces, \cdot in latex
const prec_pre_Plus = 20 # prefix +a not used
const prec_pre_Minus = 21 # prefix -a
const prec_pre_Times = 22 # prefix *a not used
const prec_pre_Divide = 23 # prefix /b not used
const prec_inf_Power = 30 # infix a^b
const prec_post_call = 99 # a(b) i.e. whether a+b(c) is (a+b)(c) vs a+(b(c))
const prec_post_ref = 100 # a[b]
const prec_post_FractionBox = 50 # precedence for a/b in 2d form
const prec_post_SuperscriptBox = 51 # precedence for a^b in 2d form
################################################################################
#
# Expression to string
#
################################################################################
function expr_to_string(@nospecialize(obj))
return sprint(show_obj, MIME("text/plain"), obj)
end
function expr_to_latex_string(@nospecialize(obj))
return sprint(show_obj, MIME("text/latex"), obj)
end
function obj_to_string(@nospecialize(obj); context = nothing)
return sprint(show_via_expressify, MIME("text/plain"), obj, context = context)
end
# parenthesize obj as if it were a term in a product
function obj_to_string_wrt_times(@nospecialize(obj); context = nothing)
io = IOBuffer()
S = AbstractAlgebra.printer(io)
print_obj(S, MIME("text/plain"),
canonicalize(expressify(obj, context = context)),
prec_inf_Times, prec_inf_Times)
finish(S)
return String(take!(io))
end
function obj_to_latex_string(@nospecialize(obj); context = nothing)
return sprint(show_via_expressify, MIME("text/latex"), obj, context = context)
end
function Base.show(io::IO, mi::MIME"text/latex", x::Union{RingElem, NCRingElem, MatrixElem})
if isdefined(Main, :IJulia) && Main.IJulia.inited
error("Dummy error for jupyter")
end
show_via_expressify(io, mi, x)
end
function Base.show(io::IO, mi::MIME"text/html", x::Union{RingElem, NCRingElem, MatrixElem})
if isdefined(Main, :IJulia) && Main.IJulia.inited &&
!AbstractAlgebra.get_html_as_latex()
error("Dummy error for jupyter")
end
if AbstractAlgebra.get_html_as_latex()
io = IOContext(io, :size_limit => 1000)
end
show_via_expressify(io, mi, x)
end
function show_via_expressify(io::IO, @nospecialize(obj); context = nothing)
show_via_expressify(io::IO, MIME("text/plain"), obj, context = context)
end
function show_via_expressify(io::IO, mi::MIME, @nospecialize(obj); context = nothing)
show_obj(io, mi, canonicalize(expressify(obj, context = context)))
end
# the low-level workhorse
function show_obj(io::IO, mi::MIME, obj)
S = printer(io)
print_obj(S, mi, obj, prec_lowest, prec_lowest)
finish(S)
end
global _html_as_latex = Ref{Bool}(false)
@doc raw"""
get_html_as_latex()
Returns whether MIME type `text/html` is printed as `text/latex`.
"""
get_html_as_latex() = _html_as_latex[]
@doc raw"""
set_html_as_latex(fl::Bool)
Toggles whether MIME type `text/html` should be printed as `text/latex`. Note
that this is a global option. The return value is the old value.
"""
function set_html_as_latex(fl::Bool)
old = get_html_as_latex()
_html_as_latex[] = fl
return old
end
function show_obj(io::IO, mi::MIME"text/html", obj)
if _html_as_latex[]
print(io, "\$")
show_obj(io, MIME("text/latex"), obj)
print(io, "\$")
else
#print(io, "<font face=\"mono\">")
show_obj(io, MIME("text/plain"), obj)
#print(io, "</font>")
end
end
################################################################################
#
# Expressify
#
################################################################################
# The definitive guide to how Expr's are printed is the print_obj function
# below. Here is a quick summary of the latex behaviour:
# * Expr(:call, ://, a, b) will create a fraction box
# * Expr(:call, :/, a, b) will not create a fraction box
# * heads :vcat, :hcat, and :row can be used to make arrays
# * Expr(:latex_form, a, b) uses b for latex output and a otherwise
# * Expr(:matrix, m) is a hint that m is a matrix, i.e. enclosed in ()
# * Expr(:text, ...) instructs string arguments to be wrapped in \text{}
# * Symbol leaves themselves have some special transformations:
# Symbol("a") => a
# Symbol("α") => {\alpha}
# Symbol("x1") => \operatorname{x1}
# Symbol("xy_1") => \operatorname{xy}_{1}
# Symbol("sin") => \operatorname{sin}
# Symbol("sin_cos") => \operatorname{sin\_cos}
# Symbol("sin_1") => \operatorname{sin}_{1}
# Symbol("sin_cos_1") => \operatorname{sin\_cos}_{1}
# Symbol("αaβb_1_2") => \operatorname{{\alpha}a{\beta}b}_{1,2}
# * various sequential constructs:
# Expr(:call, a, b, c) => a(b,c)
# Expr(:ref, a, b, c) => a[b,c]
# Expr(:vcat, a, b) => [a;b] (actually vertical in latex)
# Expr(:vect, a, b) => [a,b]
# Expr(:tuple, a, b) => (a,b)
# Expr(:list, a, b) => {a,b}
# Expr(:series, a, b) => a,b
# Expr(:sequence, a, b) => ab
# Expr(:row, a, b) => a b
# Expr(:hcat, a, b) => a b
function expressify(@nospecialize(a); context = nothing)
return sprint(print, a; context = context)::String
end
# Only when AbstractAlgebra.expressify(a::T; context = nothing) has been
# defined may enable_all_show_via_expressify be used.
# AA defines Base.show for "text/latex" and "text/html" for a general set
# of x, but for backward compatibility it is not defined for general x and
# "text/plain" or the mime-less version.
# Rationale: when neither Base.show nor AA.expressify is defined for T, then,
# since expressify calls Base.show for backward compatibility, a definition of
# Base.show in terms of expressify would give a stack overflow.
#
# We have to be careful for jupyter. When jupyter prints an object x through
# IJulia.jl, it collects sprint(show, m, x) for all m in
# [ "text/plain", "text/html", "text/latex" ... ]
# and then picks one according to some precedence. If there is a string for
# either "text/html" or "text/latex", it will *not* use "text/plain". But
# "text/plain" is the only thing which will trigger rendering using a monospace
# font (hence it will look like "code"). This explains why all julia base
# objects are printed using monospace: none of these objects has print methods
# for text/html or text/latex.
#
# The challenge for us is that we always want to define text/latex and
# text/html methods for sprint and friends. This has the disadvantage that if
# get_html_as_latex()== false, then our objects will print their ordinary
# string presentation, but since it is coming from text/html, it will be
# rendered using the "normal" font.
#
# Thus, inside IJulia we will throw an error for text/latex (always) and
# text/html (unless get_html_as_latex()).
#
# Super easy!
macro enable_all_show_via_expressify(T)
return quote
function Base.show(io::IO, x::$(esc(T)))
AbstractAlgebra.show_via_expressify(io, x)
end
function Base.show(io::IO, mi::MIME"text/plain", x::$(esc(T)))
AbstractAlgebra.show_via_expressify(io, mi, x)
end
function Base.show(io::IO, mi::MIME"text/latex", x::$(esc(T)))
if isdefined(Main, :IJulia) && Main.IJulia.inited
error("Dummy error for jupyter")
end
return AbstractAlgebra.show_via_expressify(io, mi, x)
end
function Base.show(io::IO, mi::MIME"text/html", x::$(esc(T)))
if isdefined(Main, :IJulia) && Main.IJulia.inited &&
!AbstractAlgebra.get_html_as_latex()
error("Dummy error for jupyter")
end
return AbstractAlgebra.show_via_expressify(io, mi, x)
end
end
end
################################################################################
#
# Canonicalization
#
################################################################################
# Canonicalization performs the following transformations
# a+(b+c) => a+b+c sums are flattened
# a*(b*c) => a*b*c products are flattened
# a*-b*c => -a*b*c unary minus can move freely through products
# (-a)/b => -(a/b) unary minus can move through the numerator of a quotient
# a-b => a + -b subtraction is turned into addition with unary minus
# --a => a
# 0*a => 0
# 0+a => a
# 1*a => a
# since unary minus has a higher precedence than * and /, we maintain
# -a*b*c as (-a)*b*c and not as -(a*b*c) because the former prints without ()
# is obj a call to op with 1 or more arguments
function isaExprOp(@nospecialize(obj), op::Symbol)
return isa(obj, Expr) &&
length(obj.args) > 1 &&
obj.head === :call &&
obj.args[1] === op
end
# is obj a call to op with len arguments
function isaExprOp(@nospecialize(obj), op::Symbol, len::Int)
return isa(obj, Expr) &&
length(obj.args) == len + 1 &&
obj.head === :call &&
obj.args[1] === op
end
# syntactic zeros can be removed from sums and turn a product into 0
is_syntactic_zero(obj::Number) = iszero(obj)
is_syntactic_zero(obj) = false
# syntactic ones can be removed from products
is_syntactic_one(obj::Number) = isone(obj)
is_syntactic_one(obj) = false
function get_syntactic_sign_abs(obj::Number)
return obj < 0 ? (-1, -obj) : (1, obj)
end
function get_syntactic_sign_abs(obj::Expr)
if obj.head !== :call
return (1, obj)
end
if length(obj.args) == 2 && obj.args[1] === :-
# unary minus is negative
(sgn, abs) = get_syntactic_sign_abs(obj.args[2])
return (-sgn, obj.args[2])
elseif length(obj.args) > 2 && obj.args[1] === :*
# product is negative if first term is
(sgn, abs) = get_syntactic_sign_abs(obj.args[2])
if sgn > 0
return (1, obj)
else
newobj = Expr(obj.head)
newobj.args = copy(obj.args)
newobj.args[2] = abs
if is_syntactic_one(newobj.args[2])
deleteat!(newobj.args, 2)
end
if length(newobj.args) == 2
return (sgn, newobj.args[2])
else
return (sgn, newobj)
end
end
elseif length(obj.args) == 3 && (obj.args[1] === :/ || obj.args[1] === ://)
# quotient is negative if numerator is
(sgn, abs) = get_syntactic_sign_abs(obj.args[2])
if sgn > 0
return (1, obj)
else
newobj = Expr(obj.head)
newobj.args = copy(obj.args)
newobj.args[2] = abs
return (sgn, newobj)
end
else
return (1, obj)
end
end
function get_syntactic_sign_abs(obj)
return (1, obj)
end
function syntactic_neg!(obj::Expr)
if isaExprOp(obj, :*) || isaExprOp(obj, :/) || isaExprOp(obj, ://)
obj.args[2] = syntactic_neg!(obj.args[2])
return obj
elseif isaExprOp(obj, :-, 1)
return obj.args[2]
else
return Expr(:call, :-, obj)
end
end
function syntactic_neg!(obj)
return Expr(:call, :-, obj)
end
# not actually implemented recursively to avoid stack overflow
function flatten_recursive!(ans::Expr, obj::Expr, op::Symbol)
stack = reverse(obj.args[2:end])
while !isempty(stack)
top = pop!(stack)
if isaExprOp(top, op)
for i in length(top.args):-1:2
push!(stack, top.args[i])
end
else
push!(ans.args, top)
end
end
end
# op(op(a,b),op(c,d)) => op(a,b,c,d) etc
function flatten_op(obj::Expr, op::Symbol)
if !isaExprOp(obj, op)
return obj
end
for i in 2:length(obj.args)
if isaExprOp(obj.args[i], op)
ans = Expr(:call, op)
flatten_recursive!(ans, obj, op)
return ans
end
end
return obj
end
function canonicalizePlusFinal!(obj::Expr)
@assert obj.head === :call && obj.args[1] === :+
if length(obj.args) < 2
return 0
elseif length(obj.args) == 2
return obj.args[2]
end
obj = flatten_op(obj, :+)
for i in 3:length(obj.args)
(sign, abs) = get_syntactic_sign_abs(obj.args[i])
if sign < 0
obj.args[i] = Expr(:call, :-, abs)
else
obj.args[i] = abs
end
end
return obj
end
function canonicalizePlus(obj::Expr)
@assert obj.head === :call && obj.args[1] === :+
if length(obj.args) < 2
return 0
elseif length(obj.args) == 2
return canonicalize(obj.args[2])
end
# this flatten is just to try to avoid stack overflows in canonicalize
obj = flatten_op(obj, :+)
newobj = Expr(:call, :+)
for i in 2:length(obj.args)
t = canonicalize(obj.args[i])
if !is_syntactic_zero(t)
push!(newobj.args, t)
end
end
# now do the real flatten
return canonicalizePlusFinal!(newobj)
end
function canonicalizeMinus(obj::Expr)
@assert obj.head === :call && obj.args[1] === :-
if length(obj.args) < 2
return 0
elseif length(obj.args) == 2
return syntactic_neg!(canonicalize(obj.args[2]))
end
newobj = Expr(:call, :+)
for i in 2:length(obj.args)
t = canonicalize(obj.args[i])
if !is_syntactic_zero(t)
push!(newobj.args, i > 2 ? syntactic_neg!(t) : t)
end
end
return canonicalizePlusFinal!(newobj)
end
function canonicalizeTimes(obj::Expr)
op = obj.args[1]
@assert obj.head === :call && (op === :* || op === :cdot)
if length(obj.args) < 2
return 1
elseif length(obj.args) == 2
return canonicalize(obj.args[2])
end
if op === :cdot
return canonicalize_general_recursive(obj)
end
obj = flatten_op(obj, op)
newobj = Expr(:call, op)
newsign = 1
for i in 2:length(obj.args)
t = canonicalize(obj.args[i])
if is_syntactic_zero(t)
return 0
else
(sign, abs) = get_syntactic_sign_abs(t)
newsign *= sign
if !is_syntactic_one(abs)
push!(newobj.args, abs)
end
end
end
if length(newobj.args) < 2
newobj = 1
elseif length(newobj.args) == 2
newobj = newobj.args[2]
else
newobj = flatten_op(newobj, op)
end
if newsign < 0
newobj = syntactic_neg!(newobj)
end
return newobj
end
function canonicalize_general_recursive(obj::Expr)
newobj = Expr(obj.head)
for i in obj.args
push!(newobj.args, canonicalize(i))
end
return newobj
end
function canonicalize(obj::Expr)
if obj.head === :call && !isempty(obj.args)
if obj.args[1] === :+
return canonicalizePlus(obj)
elseif obj.args[1] === :-
return canonicalizeMinus(obj)
elseif obj.args[1] === :* || obj.args[1] === :cdot
return canonicalizeTimes(obj)
end
end
return canonicalize_general_recursive(obj)
end
#fallback
function canonicalize(obj)
return obj
end
################################################################################
#
# Printing
#
################################################################################
mutable struct printer{IOT <: IO}
io::IOT
array::Vector{String}
# if terse_level is positive we print a+b instead of a + b
terse_level::Int
size_limit_stack::Vector{Int} # >= 0 for loosely-defined limit before ...
# < 0 for unrestricted output
end
function printer(io::IO)
terse_level = get(io, :terse_level, 0)
size_limit = get(io, :size_limit, -1)
return printer{typeof(io)}(io, String[], terse_level, Int[size_limit])
end
# TODO since the subexpressions are not changing much, cache the leaf_count
# so that subexpressions don't have bad quadratic behavior
function leaf_count(S::printer, obj::Expr)
z = 0
for i in obj.args
z += leaf_count(S, i)
end
return z
end
function leaf_count(S::printer, obj)
return 1
end
# size_limit is a rough limit on the number of leaves printed
function size_limit(S::printer)
return S.size_limit_stack[end]
end
function set_size_limit(S::printer, l::Int)
push!(S.size_limit_stack, l)
end
function restore_size_limit(S::printer)
pop!(S.size_limit_stack)
end
# maintain the last few printed things for token (un)mashing purposes
function push(S::printer, s::String)
while length(S.array) > 3
print(S.io, popfirst!(S.array))
end
push!(S.array, s)
end
function push_left_parenthesis(S::printer, ::MIME)
push(S, "(")
end
function push_right_parenthesis(S::printer, ::MIME)
push(S, ")")
end
function push_left_parenthesis(S::printer, ::MIME"text/latex")
push(S, "\\left(")
end
function push_right_parenthesis(S::printer, ::MIME"text/latex")
push(S, "\\right)")
end
function push_left_bracket(S::printer, ::MIME)
push(S, "[")
end
function push_right_bracket(S::printer, ::MIME)
push(S, "]")
end
function push_left_bracket(S::printer, ::MIME"text/latex")
push(S, "\\left[")
end
function push_right_bracket(S::printer, ::MIME"text/latex")
push(S, "\\right]")
end
function push_left_curly(S::printer, ::MIME)
push(S, "{")
end
function push_right_curly(S::printer, ::MIME)
push(S, "}")
end
function push_left_curly(S::printer, ::MIME"text/latex")
push(S, "\\left{")
end
function push_right_curly(S::printer, ::MIME"text/latex")
push(S, "\\right}")
end
function push_elision(S, ::MIME)
push(S, "...")
end
function push_elision(S, ::MIME"text/latex")
push(S, "{\\ldots}")
end
function finish(S::printer)
while !isempty(S.array)
print(S.io, popfirst!(S.array))
end
end
# determine the limits for the subexpressions of a given expression
# look at obj.args[offset + 1], ..., obj.args[offset + n]
function child_limits(S::printer, obj::Expr, off::Int, n::Int)
l = max(1, size_limit(S))
if n > l
leaf_counts = Int[leaf_count(S, obj.args[off +
(2*i <= l + 1 ? i : i + n - l)]) for i in 1:l]
n = l
else
leaf_counts = Int[leaf_count(S, obj.args[off + i]) for i in 1:n]
end
total_leaf_count = sum(leaf_counts)
a = Int[] # will be limits for the terms from the start
b = Int[] # will be limits for the terms from the end
abtotal = 0
while length(a) + length(b) < n
ai = 1 + length(a)
bi = n - length(b)
if length(a) < length(b) || (length(a) == length(b) &&
leaf_counts[ai] <= leaf_counts[bi])
t = max(min(3, leaf_counts[ai]), div(leaf_counts[ai]*l, total_leaf_count))
if leaf_counts[ai] < l/32
t = max(t, leaf_counts[ai])
end
push!(a, min(t, l))
else
t = max(min(3, leaf_counts[bi]), div(leaf_counts[bi]*l, total_leaf_count))
if leaf_counts[bi] < l/32
t = max(t, leaf_counts[bi])
end
push!(b, min(t, l))
end
abtotal += t
abtotal < l || break
end
return a, b
end
function compare_op_string(mi::MIME, op)
if op === :(==)
return "="
else
return string(op)::String
end
end
function compare_op_string(mi::MIME"text/latex", op)
if op === :(==)
return "="
elseif op === :(<=)
return "\\le"
elseif op === :(>=)
return "\\ge"
elseif op === :(!=)
return "\\neq"
else
return string(op)::String
end
end
function print_comparison(S::printer, mi::MIME, obj::Expr,
left::Int, right::Int, prec::Int)
n = length(obj.args)
@assert isodd(n) && n > 1
sep = S.terse_level > 0 ? "" : " "
needp = prec <= left || prec <= right
if needp
left = right = prec_lowest
push_left_parenthesis(S, mi)
end
print_obj(S, mi, obj.args[1], left, prec)
for i in 2:2:n-3
push(S, sep*compare_op_string(mi, obj.args[i])*sep)
print_obj(S, mi, obj.args[i+1], prec, prec)
end
push(S, sep*compare_op_string(mi, obj.args[n-1])*sep)
print_obj(S, mi, obj.args[n], prec, right)
if needp
push_right_parenthesis(S, mi)
end
end
# dir > 0 left associate: +, -, *, /
# dir < 0 right associative: ^
# dir = 0 non associative:
function printGenericInfix(S::printer, mi::MIME, obj::Expr,
left::Int, right::Int,
op::String, prec::Int, dir::Int)
n = length(obj.args)
if n < 3
print_call_or_ref(S, mi, obj, left, right)
return
end
needp = prec <= left || prec <= right
if needp
left = right = prec_lowest
push_left_parenthesis(S, mi)
end
if size_limit(S) < 0
# printing with no restriction
print_obj(S, mi, obj.args[2], left, prec - (dir > 0))
for i in 3:(n - 1)
push(S, op)
print_obj(S, mi, obj.args[i], prec, prec)
end
push(S, op)
print_obj(S, mi, obj.args[n], prec - (dir < 0), right)
elseif size_limit(S) == 0
# no space to print anything
push_elision(S, mi)
else
n -= 1
a, b = child_limits(S, obj, 1, n)
wrote_elision = false
for i in 1:n
if i <= length(a)
set_size_limit(S, a[i])
elseif n - i + 1 <= length(b)
set_size_limit(S, b[n - i + 1])
else
if !wrote_elision
i == 1 || push(S, op)
push_elision(S, mi)
end
wrote_elision = true
continue
end
i == 1 || push(S, op)
print_obj(S, mi, obj.args[i + 1],
i == 1 ? left : i == n ? prec - (dir < 0) : prec,
i == 1 ? prec - (dir > 0) : i == n ? right : prec)
restore_size_limit(S)
end
end
if needp
push_right_parenthesis(S, mi)
end
end
function printGenericPrefix(S::printer, mi::MIME, obj::Expr,
left::Int, right::Int,
op::String, prec::Int)
@assert length(obj.args) == 2
needp = prec <= right
if needp
left = right = prec_lowest
push_left_parenthesis(S, mi)
end
push(S, op)
print_obj(S, mi, obj.args[2], prec, right)
if needp
push_right_parenthesis(S, mi)
end
end
function printPlusArg(S::printer, mi::MIME, obj::Expr, i::Int,
left::Int, right::Int, prec::Int)
n = length(obj.args)
if i == 1
print_obj(S, mi, obj.args[2], left, prec - 1)
else
arg = obj.args[i + 1]
if isaExprOp(arg, :-, 1)
push(S, S.terse_level > 0 ? "-" : " - ")
arg = arg.args[2]
left_prec = prec_inf_Minus
else
push(S, S.terse_level > 0 ? "+" : " + ")
left_prec = prec_inf_Plus
end
right_prec = i + 2 > n ? right :
isaExprOp(obj.args[i + 2], :-, 1) ? prec_inf_Minus :
prec_inf_Plus
print_obj(S, mi, arg, left_prec, right_prec)
end
end
# special override for plus which seeks the sign of its arguments
function printPlus(S::printer, mi::MIME, obj::Expr,
left::Int, right::Int)
n = length(obj.args)
@assert n > 0 && obj.head === :call && obj.args[1] === :+
if n < 2
print_call_or_ref(S, mi, obj, left, right)
return
elseif n == 2
printGenericPrefix(S, mi, obj, left, right, "+", prec_pre_Plus)
return
end
prec = prec_inf_Plus
needp = prec <= left || prec <= right
if needp
left = right = prec_lowest
push_left_parenthesis(S, mi)
end
n -= 1
if size_limit(S) < 0
for i in 1:n
printPlusArg(S, mi, obj, i, left, right, prec)
end
elseif size_limit(S) == 0
push_elision(S, mi)
else
a, b = child_limits(S, obj, 1, n)
wrote_elision = false
for i in 1:n
if i <= length(a)
set_size_limit(S, a[i])
elseif n - i + 1 <= length(b)
set_size_limit(S, b[n - i + 1])
else
if !wrote_elision
i == 1 || push(S, S.terse_level > 0 ? "+" : " + ")
push_elision(S, mi)
end
wrote_elision = true
continue
end
printPlusArg(S, mi, obj, i, left, right, prec)
restore_size_limit(S)
end
end
if needp
push_right_parenthesis(S, mi)
end
end
# special override for unary minus
function printMinus(S::printer, mi::MIME, obj::Expr,
left::Int, right::Int)
n = length(obj.args)
@assert n > 0 && obj.head === :call && obj.args[1] === :-
if n < 2
print_call_or_ref(S, mi, obj, left, right)
elseif n == 2
printGenericPrefix(S, mi, obj, left, right, "-", prec_pre_Minus)
else
op = S.terse_level > 0 ? "-" : " - "
printGenericInfix(S, mi, obj, left, right, op, prec_inf_Minus, 1)
end
end
function printFraction(S::printer, mi::MIME"text/latex",
@nospecialize(num), @nospecialize(den),
left::Int, right::Int)
prec = prec_post_FractionBox
needp = prec <= left || prec <= right
if needp
left = right = prec_lowest
push_left_parenthesis(S, mi)
end
push(S, "\\frac{")
print_obj(S, mi, num, prec_lowest, prec_lowest)
push(S, "}{")
print_obj(S, mi, den, prec_lowest, prec_lowest)
push(S, "}")
if needp
push_right_parenthesis(S, mi)
end
end
function printDivides(S::printer, mi::MIME"text/latex", obj::Expr,
left::Int, right::Int)
n = length(obj.args)
@assert n > 0 && obj.head === :call && obj.args[1] === ://
if n != 3
printGenericInfix(S, mi, obj, left, right, "//", prec_inf_Divide, +1)
else
(sgn, abs) = get_syntactic_sign_abs(obj.args[2])
if sgn < 0
prec = prec_pre_Minus
needp = prec <= right
if needp
left = right = prec_lowest
push_left_parenthesis(S, mi)
end
push(S, "-")
printFraction(S, mi, abs, obj.args[3], prec, right)
if needp
push_right_parenthesis(S, mi)
end
else
printFraction(S, mi, abs, obj.args[3], left, right)
end
end
end
function printPower(S::printer, mi::MIME"text/latex", obj::Expr,
left::Int, right::Int)
n = length(obj.args)
@assert n > 0 && obj.head === :call && obj.args[1] === :(^)
if n != 3
printGenericInfix(S, mi, obj, left, right, "^", prec_inf_Power, +1)
else
prec = prec_post_SuperscriptBox
needp = prec <= left || prec <= right
if needp
left = right = prec_lowest
push_left_parenthesis(S, mi)
end
print_obj(S, mi, obj.args[2], left, prec)
push(S, "^{")
print_obj(S, mi, obj.args[3], prec_lowest, prec_lowest)
push(S, "}")
if needp
push_right_parenthesis(S, mi)
end
end
end
function print_call_or_ref(S::printer, mi::MIME, obj::Expr,
left::Int, right::Int)
n = length(obj.args)
@assert n > 0 && (obj.head === :call || obj.head === :ref)
prec = obj.head === :call ? prec_post_call : prec_post_ref
needp = prec <= left
if needp
left = prec_lowest
push_left_parenthesis(S, mi)