Decoding HTML entities in Emacs/Elisp

Some online websites like to encode all their text through HTML entities, so instead of seeing a text like

So I'm looking

You get something like:

So I'm looking 

I was wondering if there's a built in way to开发者_JS百科 translate the encoded text to regular text using any Emacs built-ins or if I should declare my map of strings ("&83" => "S"...) and manually decode it using a map.

Any pointers would be greatly appreciated.

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I wrote this function to deal with non-numeric unicode entities, in case anybody needs.

(defun html-entities-to-unicode (string)
  (let* ((plist '(Aacute "Á" aacute "á" Acirc "Â" acirc "â" acute "´" AElig "Æ" aelig "æ" Agrave "À" agrave "à" alefsym "ℵ" Alpha "Α" alpha "α" amp "&" and "∧" ang "∠" apos "'" aring "å" Aring "Å" asymp "≈" atilde "ã" Atilde "Ã" auml "ä" Auml "Ä" bdquo "„" Beta "Β" beta "β" brvbar "¦" bull "•" cap "∩" ccedil "ç" Ccedil "Ç" cedil "¸" cent "¢" Chi "Χ" chi "χ" circ "ˆ" clubs "♣" cong "≅" copy "©" crarr "↵" cup "∪" curren "¤" Dagger "‡" dagger "†" darr "↓" dArr "⇓" deg "°" Delta "Δ" delta "δ" diams "♦" divide "÷" eacute "é" Eacute "É" ecirc "ê" Ecirc "Ê" egrave "è" Egrave "È" empty "∅" emsp " " ensp " " Epsilon "Ε" epsilon "ε" equiv "≡" Eta "Η" eta "η" eth "ð" ETH "Ð" euml "ë" Euml "Ë" euro "€" exist "∃" fnof "ƒ" forall "∀" frac12 "½" frac14 "¼" frac34 "¾" frasl "⁄" Gamma "Γ" gamma "γ" ge "≥" gt ">" harr "↔" hArr "⇔" hearts "♥" hellip "…" iacute "í" Iacute "Í" icirc "î" Icirc "Î" iexcl "¡" igrave "ì" Igrave "Ì" image "ℑ" infin "∞" int "∫" Iota "Ι" iota "ι" iquest "¿" isin "∈" iuml "ï" Iuml "Ï" Kappa "Κ" kappa "κ" Lambda "Λ" lambda "λ" lang "〈" laquo "«" larr "←" lArr "⇐" lceil "⌈" ldquo "“" le "≤" lfloor "⌊" lowast "∗" loz "◊" lrm "" lsaquo "‹" lsquo "‘" lt "<" macr "¯" mdash "—" micro "µ" middot "·" minus "−" Mu "Μ" mu "μ" nabla "∇" nbsp "" ndash "–" ne "≠" ni "∋" not "¬" notin "∉" nsub "⊄" ntilde "ñ" Ntilde "Ñ" Nu "Ν" nu "ν" oacute "ó" Oacute "Ó" ocirc "ô" Ocirc "Ô" OElig "Œ" oelig "œ" ograve "ò" Ograve "Ò" oline "‾" omega "ω" Omega "Ω" Omicron "Ο" omicron "ο" oplus "⊕" or "∨" ordf "ª" ordm "º" oslash "ø" Oslash "Ø" otilde "õ" Otilde "Õ" otimes "⊗" ouml "ö" Ouml "Ö" para "¶" part "∂" permil "‰" perp "⊥" Phi "Φ" phi "φ" Pi "Π" pi "π" piv "ϖ" plusmn "±" pound "£" Prime "″" prime "′" prod "∏" prop "∝" Psi "Ψ" psi "ψ" quot "\"" radic "√" rang "〉" raquo "»" rarr "→" rArr "⇒" rceil "⌉" rdquo "”" real "ℜ" reg "®" rfloor "⌋" Rho "Ρ" rho "ρ" rlm "" rsaquo "›" rsquo "’" sbquo "‚" scaron "š" Scaron "Š" sdot "⋅" sect "§" shy "" Sigma "Σ" sigma "σ" sigmaf "ς" sim "∼" spades "♠" sub "⊂" sube "⊆" sum "∑" sup "⊃" sup1 "¹" sup2 "²" sup3 "³" supe "⊇" szlig "ß" Tau "Τ" tau "τ" there4 "∴" Theta "Θ" theta "θ" thetasym "ϑ" thinsp " " thorn "þ" THORN "Þ" tilde "˜" times "×" trade "™" uacute "ú" Uacute "Ú" uarr "↑" uArr "⇑" ucirc "û" Ucirc "Û" ugrave "ù" Ugrave "Ù" uml "¨" upsih "ϒ" Upsilon "Υ" upsilon "υ" uuml "ü" Uuml "Ü" weierp "℘" Xi "Ξ" xi "ξ" yacute "ý" Yacute "Ý" yen "¥" yuml "ÿ" Yuml "Ÿ" Zeta "Ζ" zeta "ζ" zwj "" zwnj ""))
         (get-function (lambda (s) (or (plist-get plist (intern (substring s 1 -1))) s))))
    (replace-regexp-in-string "&[^; ]*;" get-function string)))

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I wrote the following, which does what you need, @federico-builes. (I needed the same thing.)

(defun ajs-decimal-escapes-to-unicode (start end)
  "Convert escapes like 'λ' to Unicode like 'λ'.
Operates on the active region or the whole buffer."
  (interactive (list (point) (mark)))
  (or (use-region-p)
      (setq start (point-min) end (point-max)))
  (insert (replace-regexp-in-string
           "&#[0-9]*;"
           (lambda (match)
             (format "%c" (string-to-number (substring match 2 -1))))
           (filter-buffer-substring start end t))))

@konr's response was helpful - thanks! I've also been enjoying An Introduction to Programming in Emacs Lisp. This is the first Lisp I've written that might be useful. I'd appreciate feedback, even on things like whitespace; thanks!

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Don't know if there is a built in function, but this small function can do the job:

(defun my-insert-encode-entities-string (str)
  (mapconcat
   (lambda (char) (format "&#%d;" char))
   (string-to-list str)
   ""))

If you only wish to encode HTML entities, use url-insert-entities-in-string instead.