fix #61: use the internal .env to manage the automatically added css/…

…js assets instead of manipulating the `meta` object directly, otherwise `css` would be present in `meta` when math/mermaid/prism is used and the default css wouldn't be added

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: litedown
 Type: Package
 Title: A Lightweight Version of R Markdown
-Version: 0.4.10
+Version: 0.4.11
 Authors@R: c(
    person("Yihui", "Xie", role = c("aut", "cre"), email = "[email protected]", comment = c(ORCID = "0000-0003-0645-5666", URL = "https://yihui.org")),
    person()

NEWS.md

@@ -18,6 +18,8 @@
 
 - Added an argument `examples` to `pkg_manual()` to run examples and show their output (thanks, @TimTaylor, #54).
 
+- Fixed a bug that the default CSS wouldn't be added when a math expression exists on the page (thanks, @calvinw, #61).
+
 - Fixed a bug that cross-references to other chapters of a book could not be resolved when previewing a single chapter.
 
 - Fixed a bug that the file navigation by line numbers on code blocks stopped working in `litedown::roam()` due to yihui/lite.js@5e06d19.

R/mark.R

@@ -224,6 +224,8 @@ mark = function(input, output = NULL, text = NULL, options = NULL, meta = list()
     maths[x]
   })
 
+  has_mermaid = FALSE
+
   if (format == 'html') {
     # don't disable check boxes
     ret = gsub('(<li><input type="checkbox" [^>]*?)disabled="" (/>)', '\\1\\2', ret)
@@ -255,12 +257,8 @@ mark = function(input, output = NULL, text = NULL, options = NULL, meta = list()
     }, perl = FALSE)  # for perl = TRUE, we'd need (?s) before (.+?)
     # support mermaid
     r_mmd = '<pre><code class="language-mermaid">(.*?)</code></pre>'
-    if (length(grep(r_mmd, ret))) {
+    if (has_mermaid <- length(grep(r_mmd, ret))) {
       ret = gsub(r_mmd, '<pre class="mermaid">\\1</pre>', ret)
-      # add the js asset automatically if not detected
-      if (length(grep('mermaid', meta[['js']])) == 0) meta = add_meta(
-        meta, c(js = '@npm/mermaid/dist/mermaid.min.js')
-      )
     }
     r4 = '(<pre><code class="language-)\\{([^"]+)}">'
     # deal with ```{.class1 .class2 attrs}, which is not supported by commonmark
@@ -287,14 +285,13 @@ mark = function(input, output = NULL, text = NULL, options = NULL, meta = list()
     if (isTRUE(options[['number_sections']])) ret = number_sections(ret)
     # build table of contents
     ret = add_toc(ret, options)
-    # add js/css for math
+    # math
     if (!has_math) has_math = length(ret) && (
       grepl('$$</p>', ret, fixed = TRUE) || grepl('\\)</span>', ret, fixed = TRUE)
     )  # math may be from pkg_manual()'s HTML
     is_katex = TRUE
     if (has_math && length(js_math <- js_options(options[['js_math']], 'katex'))) {
       is_katex = js_math$package == 'katex'
-      meta = set_math(meta, js_math, is_katex)
     }
     # number figures and tables, etc.
     ret = number_refs(ret, r_ref, is_katex)
@@ -358,10 +355,20 @@ mark = function(input, output = NULL, text = NULL, options = NULL, meta = list()
   clever = isTRUE(options[['cleveref']])
   if (format == 'latex') ret = latex_refs(ret, r_ref, clever) else clever = FALSE
 
-  meta$body = I(ret)
-
   # use the template (if provided) to create a standalone document
   if (is.character(template)) {
+    meta$body = I(ret)
+    if (format == 'html') {
+      # clear the internal js/css
+      on.exit(rm(list = c('js', 'css'), envir = .env), add = TRUE)
+      # add js/css for math
+      if (has_math) set_math(js_math, is_katex)
+      # add js/css for syntax highlighting
+      set_highlight(options, ret)
+      # add js for mermaid
+      if (has_mermaid && length(grep('mermaid', meta[['js']])) == 0)
+        set_meta(js = '@npm/mermaid/dist/mermaid.min.js')
+    }
     ret = build_output(
       format, options, template, meta, test = c(if (length(input)) dirname(input), '.')
     )
@@ -409,19 +416,13 @@ mark = function(input, output = NULL, text = NULL, options = NULL, meta = list()
 build_output = function(format, options, template, meta, ...) {
   tpl = one_string(template, ...)
   if (format == 'html') {
-    b = meta$body
-    set_meta = function(name, value) {
-      if (!name %in% names(meta)) meta[[name]] <<- value
-    }
-    set_meta('css', 'default')
-    set_meta('plain-title', I(str_trim(commonmark::markdown_text(meta[['title']]))))
-    meta = set_highlight(meta, options, b)
-    # if the class .line-numbers is present, add js/css for line numbers
-    if (any(grepl('<code class="[^"]*line-numbers', b))) for (i in c('css', 'js')) {
-      meta[[i]] = c(meta[[i]], '@code-line-numbers')
-    }
+    defaults = list(
+      'css' = 'default',
+      'plain-title' = I(str_trim(commonmark::markdown_text(meta[['title']])))
+    )
+    for (i in setdiff(names(defaults), names(meta))) meta[[i]] = defaults[[i]]
     # special handling for css/js "files" that have no extensions
-    for (i in c('css', 'js')) meta[[i]] = resolve_files(meta[[i]], i)
+    for (i in c('css', 'js')) meta[[i]] = resolve_files(c(meta[[i]], .env[[i]]), i)
   }
   sub_vars(tpl, meta, ...)
 }

R/package.R

@@ -149,7 +149,8 @@ pkg_desc = function(name = detect_pkg()) {
       paste0('\n<td>', d, '</td>'), '\n</tr>', collapse = '\n'
     ), '\n</tbody></table>'
   )
-  new_asis(c(pkg_style(), res))
+  set_meta(css = '@manual')
+  new_asis(res)
 }
 
 # format authors, adding URL and ORCID links as appropriate
@@ -371,11 +372,10 @@ pkg_manual = function(
   res = gsub('<code class="language-R"', '<code class="language-r"', res, fixed = TRUE)
   res = gsub('&#8288;', '', res, fixed = TRUE)
   res = gsub('<table>', '<table class="table-full">', res, fixed = TRUE)
-  new_asis(c(pkg_style(), toc, res))
+  set_meta(css = '@manual')
+  new_asis(c(toc, res))
 }
 
-pkg_style = function() gen_tag(jsd_resolve(jsdelivr('css/manual.min.css')))
-
 run_examples = function(html, config, path) {
   config$dev.path = path = paste0(config$dev.path, path)
   on.exit(xfun::del_empty_dir(dirname(path)), add = TRUE)

R/utils.R

@@ -204,12 +204,12 @@ restore_html = function(x) {
 }
 
 # set js/css variables according to the js_math option
-set_math = function(meta, o, is_katex) {
+set_math = function(o, is_katex) {
   if (is_katex) o$js = c(o$js, 'dist/contrib/auto-render.min.js')
   js = js_combine(sprintf('npm/%s%s/%s', o$package, o$version, o$js))
   js = if (is_katex) c(js, '@render-katex') else c('@mathjax-config', js)
   css = sprintf('@npm/%s%s/%s', o$package, o$version, o$css)
-  add_meta(meta, list(js = js, css = css))
+  set_meta(js = js, css = css)
 }
 
 # use jsdelivr's combine feature
@@ -242,16 +242,20 @@ js_libs = list(
   )
 )
 
-add_meta = function(x, v) {
-  for (i in names(v)) x[[i]] = c(v[[i]], x[[i]])
-  x
+set_meta = function(...) {
+  v = list(...)
+  for (i in names(v)) .env[[i]] = c(.env[[i]], v[[i]])
 }
 
 # set js/css variables according to the js_highlight option
-set_highlight = function(meta, options, html) {
+set_highlight = function(options, html) {
+  # if the class .line-numbers is present, add js/css for line numbers
+  if (any(grepl('<code class="[^"]*line-numbers', html)))
+    set_meta(js = '@code-line-numbers', css = '@code-line-numbers')
+
   r = '(?<=<code class="language-)([^"]+)(?=")'
-  if (!any(grepl(r, html, perl = TRUE))) return(meta)
-  if (!length(o <- js_options(options[['js_highlight']], 'prism'))) return(meta)
+  if (!any(grepl(r, html, perl = TRUE))) return()
+  if (!length(o <- js_options(options[['js_highlight']], 'prism'))) return()
 
   p = o$package
   # return jsdelivr subpaths
@@ -302,7 +306,7 @@ set_highlight = function(meta, options, html) {
   # embedding faster because each js is a separate URL that has been downloaded)
   js = if (is.null(l)) paste0('@', js) else js_combine(js)
 
-  add_meta(meta, list(js = js, css = css))
+  set_meta(js = js, css = css)
 }
 
 # figure out which language support files are needed for highlight.js/prism.js