From 3351502b8bd2a4061f447975361729f73f03d5fc Mon Sep 17 00:00:00 2001
From: Herman Sletmoen <hermansletmoen@gmail.com>
Date: Fri, 13 Dec 2024 15:19:02 +0100
Subject: [PATCH 1/3] Override default variable latexification with custom
 [latex = ...] field

---
 src/latexify_recipes.jl | 29 +++++++++++++++++++++--------
 src/variable.jl         |  6 +++---
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/latexify_recipes.jl b/src/latexify_recipes.jl
index 58dcdd3b4..a557c1ea9 100644
--- a/src/latexify_recipes.jl
+++ b/src/latexify_recipes.jl
@@ -52,8 +52,12 @@ recipe(n) = latexify_derivatives(cleanup_exprs(_toexpr(n)))
     cdot --> false
     fmt --> FancyNumberFormatter(5)
     index --> :subscript
-    snakecase --> true
-    safescripts --> true
+
+    # Prevent Latexify.jl from interfering if variable has custom [latex = ...] field (it should escape its own underscores etc.)
+    custom = unwrap(n) isa Symbolic && hasmetadata(unwrap(n), VariableLatex)
+    snakecase --> !custom
+    safescripts --> !custom
+    function_name --> false
 
     return recipe(n)
 end
@@ -191,13 +195,22 @@ function _toexpr(O)
             return frac_expr
         end
     end
-    if issym(O) 
-        sym = string(nameof(O))
-        sym = replace(sym, NAMESPACE_SEPARATOR => ".")
-        if length(sym) > 1
-            sym = string("\\mathtt{", sym, "}")
+    if issym(O)
+        name = string(nameof(O))
+
+        # If given, use custom [latex = ...] option for the variable name (does not affect subsystem names)
+        # Otherwise fall back to a sane default, where multi-letter variables are rendered with a fixed width font
+        name = replace(name, NAMESPACE_SEPARATOR => '.')
+        if hasmetadata(O, VariableLatex)
+            seppos = findlast('.', name)
+            sysname = isnothing(seppos) ? "" : "\\mathtt{$(name[begin:seppos])}" # always \mathtt system names (consistent with multi-letter vars)
+            varname = getmetadata(O, VariableLatex) # override
+            name = string(sysname, varname)
+        elseif length(name) > 1
+            name = "\\mathtt{$name}"
         end
-        return Symbol(sym)
+
+        return Symbol(name)
     end
     !iscall(O) && return O
 
diff --git a/src/variable.jl b/src/variable.jl
index 489a072de..c4b60f82c 100644
--- a/src/variable.jl
+++ b/src/variable.jl
@@ -17,6 +17,7 @@ const IndexMap = Dict{Char,Char}(
 abstract type AbstractVariableMetadata end
 struct VariableDefaultValue <: AbstractVariableMetadata end
 struct VariableSource <: AbstractVariableMetadata end
+struct VariableLatex <: AbstractVariableMetadata end
 
 function recurse_and_apply(f, x)
     if symtype(x) <: AbstractArray
@@ -252,9 +253,8 @@ function construct_vars(macroname, v, type, call_args, val, prop, transform, isr
     lhs, :($lhs = $rhs)
 end
 
-function option_to_metadata_type(::Val{opt}) where {opt}
-    throw(Base.Meta.ParseError("unknown property type $opt"))
-end
+option_to_metadata_type(::Val{:latex}) = VariableLatex
+option_to_metadata_type(::Val{opt}) where {opt} = throw(Base.Meta.ParseError("unknown property type $opt"))
 
 function setprops_expr(expr, props, macroname, varname)
     expr = :($setmetadata($expr, $VariableSource, ($(Meta.quot(macroname)), $varname,)))

From 4e3f23325380295de7e85afce3e39254e0d20bda Mon Sep 17 00:00:00 2001
From: Herman Sletmoen <hermansletmoen@gmail.com>
Date: Fri, 13 Dec 2024 15:19:24 +0100
Subject: [PATCH 2/3] Preserve latex variable metadata for callable variables

---
 src/latexify_recipes.jl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/latexify_recipes.jl b/src/latexify_recipes.jl
index a557c1ea9..c76b5eec0 100644
--- a/src/latexify_recipes.jl
+++ b/src/latexify_recipes.jl
@@ -244,6 +244,10 @@ function _toexpr(O)
         end
         return Expr(:call, :_integral, _toexpr(lower), _toexpr(upper), vars, _toexpr(integrand))
     elseif symtype(op) <: FnType
+        # Preserve latex metadata field when `x(t)` becomes `x`
+        if hasmetadata(O, VariableLatex)
+            op = setmetadata(op, VariableLatex, getmetadata(O, VariableLatex))
+        end
         isempty(args) && return nameof(op)
         return Expr(:call, _toexpr(op), _toexpr(args)...)
     elseif op === getindex && symtype(args[1]) <: AbstractArray

From 82d9eacba3ce2e9126682a33595994c392eee3ee Mon Sep 17 00:00:00 2001
From: Herman Sletmoen <hermansletmoen@gmail.com>
Date: Fri, 13 Dec 2024 15:19:37 +0100
Subject: [PATCH 3/3] Add tests

---
 test/latexify.jl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/test/latexify.jl b/test/latexify.jl
index 5d80cab52..17a47afe9 100644
--- a/test/latexify.jl
+++ b/test/latexify.jl
@@ -62,3 +62,7 @@ Dy = Differential(y)
 @test_reference "latexify_refs/indices2.txt" latexify(h[10,10], index=:bracket)
 
 @test !occursin("identity", latexify(Num(π))) # issue #1254
+
+@variables t
+@test String(latexify(only(@variables sys₊x123(t)[1:3])[1]; env=:raw)) == raw"\mathtt{sys.x123}\left( t \right)_{1}" # x without subscript
+@test String(latexify(only(@variables sys₊x123(t)[1:3] [latex = raw"x_{123}"])[1]; env=:raw)) == raw"\mathtt{sys.}x_{{123}}\left( t \right)_{1}" # x with subscript