Inline code prints negative number without sign

[fkohrt]

---
title: "Inline test"
output: html_document
---

The following prints a positive(!) number: `r (-1) * 10^7`

...leads to...

xfun::session_info('knitr')

R version 4.3.1 (2023-06-16)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 20.04.6 LTS


Locale:
  LC_CTYPE=C.UTF-8       LC_NUMERIC=C          
  LC_TIME=C.UTF-8        LC_COLLATE=C.UTF-8    
  LC_MONETARY=C.UTF-8    LC_MESSAGES=C.UTF-8   
  LC_PAPER=C.UTF-8       LC_NAME=C             
  LC_ADDRESS=C           LC_TELEPHONE=C        
  LC_MEASUREMENT=C.UTF-8 LC_IDENTIFICATION=C   

time zone: UTC
tzcode source: system (glibc)

Package version:
  evaluate_0.21   graphics_4.3.1  grDevices_4.3.1
  highr_0.10      knitr_1.44      methods_4.3.1  
  stats_4.3.1     tools_4.3.1     utils_4.3.1    
  xfun_0.40       yaml_2.3.7     

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[cderv]

I think the issue comes from this function we use for printing

knitr:::format_sci((-1)*10^7)
#> [1] "10^{7}"

We use this function in inline hooks

knitr/R/hooks-md.R

Lines 204 to 207 in 42f6b3a

	inline = function(x) {
	if (is_latex_output()) .inline.hook.tex(x) else {
	.inline.hook(format_sci(x, if (length(pandoc_to()) == 1L) 'latex' else 'html'))
	}

It seems there is several issues here:

• @yihui why do we latex as format and not HTML here ? It seems we should use html.

   knitr:::format_sci_one((-1)*10^7, format = "latex")
   #> [1] "10^{7}"
   knitr:::format_sci_one((-1)*10^7, format = "html")
   #> [1] "10<sup>7</sup>"

  Not sure I understand why we do length(pandoc_to()) == 1L then latex

• We still loose the minus sign does not seems right...
  

  knitr/R/utils.R

  Lines 206 to 207 in 42f6b3a

  	b = round_digits(x / 10^lx)
  	b[b %in% c(1, -1)] = ''

  if not -1 we keep it

   knitr:::format_sci_one(-2*10^7, 'html')
   #> [1] "-2 &times; 10<sup>7</sup>"

  shouldn't we have a special case for -1 ?

  I am in doubt with your implementation of scientific notation
  

  knitr/R/utils.R

  Lines 227 to 229 in 42f6b3a

  	sci_notation = function(format, base, times, power) {
  	sprintf(format, base, ifelse(base == '', '', times), power)
  	}

  Should it be "-1 &times; 10<sup>7</sup>" or "-10<sup>7</sup>" ?

[yihui]

Should be fixed now. Thanks for the report!

---
title: "Inline test"
output: html_document
---

The following prints a positive(!) number: $`r (-1) * 10^7`$

Note that you need $ $ around the number.

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