Minus for subtraction and minus for negative numbers not differentiated in default HTML math output

[frabjous]

Minus for subtraction and minus for negative numbers not differentiated in default HTML math output

[jgm]

I agree on all these points. Transferring this to texmath, which actually does the conversion.

[jgm]

One issue should perhaps be addressed in the tex reader:

% texmath -t native         
-1
[ ESymbol Bin "\8722" , ENumber "1" ]

Ideally this would not be parsed as a symbol in category Bin (binary operator). But this would require a bit more sophistication than we currently have in the parser.

For the other issue we have

% texmath -t native         
2 + (2 + 3)
[ ENumber "2"
, ESymbol Bin "+"
, EDelimited
    "("
    ")"
    [ Right (ENumber "2")
    , Right (ESymbol Bin "+")
    , Right (ENumber "3")
    ]
]

which is fine, but something is going on in the pandoc writer, which adds the spacing around the binary operator in one context but not the other:

% texmath -t pandoc 
2+(2+3)
[ Str "2"
, Str "\8197"
, Str "+"
, Str "\8197"
, Str "("
, Str "2"
, Str "+"
, Str "3"
, Str ")"
]

[jgm]

Pushed a change that fixes the second issue. Not yet the first.

[jgm]

Looks like we already have code in the TeX reader to change some Bins to Ops. This code is too simple; we need to look at the atom before the symbol as well as the one after it.

[jgm]

https://tex.stackexchange.com/questions/392081/how-does-tex-figure-out-whether-a-should-be-typeset-as-unary-or-binary

Texbook says:

5. If the current item is a Bin atom, and if this was the first atom
   in the list, or if the most recent previous atom was Bin, Op, Rel, Open,
   or Punct, change the current Bin to Ord and continue with Rule 14.
   Otherwise continue with Rule 17.

6. If the current item is a Rel or Close or Punct atom, and if the most
   recent previous atom was Bin, change that previous Bin to Ord. Continue with Rule 17.