gistfile1.vim

" http://vim.wikia.com/wiki/HTML_entities
" http://www.bigbaer.com/sidebars/entities/

" FIXME: you don't know how to use the -range argument! (doesn't work)
command! -range HtmlEncode <line1>,<line2>call HtmlEntities('encode')
command! -range HtmlDecode <line1>,<line2>call HtmlEntities('decode')
" TODO: only accept full lines as a range; would be nice for arbitrary selection
function! HtmlEntities(action) range
    " & -> &amp; should be the first substitution
    let entities = [
    \    ['&', '&amp;'],
    \    ['"', '&quot;'],
    \    ['<', '&lt;'],
    \    ['>', '&gt;'],
    \    ['¡', '&iexcl;'],
    \    ['¢', '&cent;'],
    \    ['£', '&pound;'],
    \    ['¤', '&curren;'],
    \    ['Â¥', '&yen;'],
    \    ['€', '&euro;'],
    \    ['¦', '&brvbar;'],
    \    ['§', '&sect;'],
    \    ['¨', '&uml;'],
    \    ['©', '&copy;'],
    \    ['ª', '&ordf;'],
    \    ['«', '&laquo;'],
    \    ['¬', '&not;'],
    \    ['®', '&reg;'],
    \    ['™', '&trade;'],
    \    ['¯', '&macr;'],
    \    ['°', '&deg;'],
    \    ['±', '&plusmn;'],
    \    ['²', '&sup2;'],
    \    ['³', '&sup3;'],
    \    ['´', '&acute;'],
    \    ['µ', '&micro;'],
    \    ['¶', '&para;'],
    \    ['·', '&middot;'],
    \    ['¸', '&cedil;'],
    \    ['¹', '&sup1;'],
    \    ['º', '&ordm;'],
    \    ['»', '&raquo;'],
    \    ['¼', '&frac14;'],
    \    ['½', '&frac12;'],
    \    ['¾', '&frac34;'],
    \    ['¿', '&iquest;'],
    \    ['×', '&times;'],
    \    ['÷', '&divide;'],
    \    ['À', '&Agrave;'],
    \    ['Á', '&Aacute;'],
    \    ['Â', '&Acirc;'],
    \    ['Ã', '&Atilde;'],
    \    ['Ä', '&Auml;'],
    \    ['Å', '&Aring;'],
    \    ['Æ', '&AElig;'],
    \    ['Ç', '&Ccedil;'],
    \    ['È', '&Egrave;'],
    \    ['É', '&Eacute;'],
    \    ['Ê', '&Ecirc;'],
    \    ['Ë', '&Euml;'],
    \    ['Ì', '&Igrave;'],
    \    ['Í', '&Iacute;'],
    \    ['Î', '&Icirc;'],
    \    ['Ï', '&Iuml;'],
    \    ['Ð', '&ETH;'],
    \    ['Ñ', '&Ntilde;'],
    \    ['Ò', '&Ograve;'],
    \    ['Ó', '&Oacute;'],
    \    ['Ô', '&Ocirc;'],
    \    ['Õ', '&Otilde;'],
    \    ['Ö', '&Ouml;'],
    \    ['Ø', '&Oslash;'],
    \    ['Ù', '&Ugrave;'],
    \    ['Ú', '&Uacute;'],
    \    ['Û', '&Ucirc;'],
    \    ['Ü', '&Uuml;'],
    \    ['Ý', '&Yacute;'],
    \    ['Þ', '&THORN;'],
    \    ['ß', '&szlig;'],
    \    ['à', '&agrave;'],
    \    ['á', '&aacute;'],
    \    ['â', '&acirc;'],
    \    ['ã', '&atilde;'],
    \    ['ä', '&auml;'],
    \    ['Ã¥', '&aring;'],
    \    ['æ', '&aelig;'],
    \    ['ç', '&ccedil;'],
    \    ['è', '&egrave;'],
    \    ['é', '&eacute;'],
    \    ['ê', '&ecirc;'],
    \    ['ë', '&euml;'],
    \    ['ì', '&igrave;'],
    \    ['í', '&iacute;'],
    \    ['î', '&icirc;'],
    \    ['ï', '&iuml;'],
    \    ['ð', '&eth;'],
    \    ['ñ', '&ntilde;'],
    \    ['ò', '&ograve;'],
    \    ['ó', '&oacute;'],
    \    ['ô', '&ocirc;'],
    \    ['õ', '&otilde;'],
    \    ['ö', '&ouml;'],
    \    ['ø', '&oslash;'],
    \    ['ù', '&ugrave;'],
    \    ['ú', '&uacute;'],
    \    ['û', '&ucirc;'],
    \    ['ü', '&uuml;'],
    \    ['ý', '&yacute;'],
    \    ['þ', '&thorn;'],
    \    ['ÿ', '&yuml;'],
    \    ['Œ', '&OElig;'],
    \    ['œ', '&oelig;'],
    \    ['Å ', '&Scaron;'],
    \    ['Å¡', '&scaron;'],
    \    ['Ÿ', '&Yuml;'],
    \    ['ˆ', '&circ;'],
    \    ['˜', '&tilde'],
    \    ['‌', '&zwnj;'],
    \    ['‍', '&zwj;'],
    \    ['‎', '&lrm;'],
    \    ['‏', '&rlm;'],
    \    ['–', '&ndash;'],
    \    ['—', '&mdash;'],
    \    ['‘', '&lsquo;'],
    \    ['’', '&rsquo;'],
    \    ['‚', '&sbquo;'],
    \    ['“', '&ldquo;'],
    \    ['”', '&rdquo;'],
    \    ['„', '&bdquo;'],
    \    ['†', '&dagger;'],
    \    ['‡', '&Dagger;'],
    \    ['‰', '&permil;'],
    \    ['‹', '&lsaquo;'],
    \    ['›', '&rsaquo;'],
    \    ['ƒ', '&fnof;'],
    \    ['•', '&bull;'],
    \    ['…', '&hellip;'],
    \    ['′', '&prime;'],
    \    ['″', '&Prime;'],
    \    ['‾', '&oline;'],
    \    ['⁄', '&frasl;'],
    \    ['℘', '&weierp;'],
    \    ['ℑ', '&image;'],
    \    ['ℜ', '&real;'],
    \    ['ℵ', '&alefsym;'],
    \    ['←', '&larr;'],
    \    ['↑', '&uarr;'],
    \    ['→', '&rarr;'],
    \    ['↓', '&darr;'],
    \    ['↔', '&harr;'],
    \    ['↵', '&crarr;'],
    \    ['⇐', '&lArr;'],
    \    ['⇑', '&uArr;'],
    \    ['⇒', '&rArr;'],
    \    ['⇓', '&dArr;'],
    \    ['⇔', '&hArr;'],
    \    ['∀', '&forall;'],
    \    ['∂', '&part;'],
    \    ['∃', '&exist;'],
    \    ['∅', '&empty;'],
    \    ['∇', '&nabla;'],
    \    ['∈', '&isin;'],
    \    ['∉', '&notin;'],
    \    ['∋', '&ni;'],
    \    ['∏', '&prod;'],
    \    ['∑', '&sum;'],
    \    ['−', '&minus;'],
    \    ['∗', '&lowast;'],
    \    ['√', '&radic;'],
    \    ['∝', '&prop;'],
    \    ['∞', '&infin;'],
    \    ['∠', '&ang;'],
    \    ['∧', '&and;'],
    \    ['∨', '&or;'],
    \    ['∩', '&cap;'],
    \    ['∪', '&cup;'],
    \    ['∫', '&int;'],
    \    ['∴', '&there4;'],
    \    ['∼', '&sim;'],
    \    ['≅', '&cong;'],
    \    ['≈', '&asymp;'],
    \    ['≠', '&ne;'],
    \    ['≡', '&equiv;'],
    \    ['≤', '&le;'],
    \    ['≥', '&ge;'],
    \    ['⊂', '&sub;'],
    \    ['⊃', '&sup;'],
    \    ['⊄', '&nsub;'],
    \    ['⊆', '&sube;'],
    \    ['⊇', '&supe;'],
    \    ['⊕', '&oplus;'],
    \    ['⊗', '&otimes;'],
    \    ['⊥', '&perp;'],
    \    ['⋅', '&sdot;'],
    \    ['⌈', '&lceil;'],
    \    ['⌉', '&rceil;'],
    \    ['⌊', '&lfloor;'],
    \    ['⌋', '&rfloor;'],
    \    ['⟨', '&lang;'],
    \    ['⟩', '&rang;'],
    \    ['◊', '&loz;'],
    \    ['℠', '&#8480'],
    \    ['℃', '&#8451;'],
    \    ['℅', '&#8453;'],
    \    ['℉', '&#8457;'],
    \    ['№', '&#8470;'],
    \    ['℗', '&#8471;'],
    \    ['℞', '&#8478;'],
    \    ['Ω', '&#8486;'],
    \    ['℧', '&#8487;'],
    \    ['☀', '&#9728;'],
    \    ['☁', '&#9729;'],
    \    ['☂', '&#9730;'],
    \    ['☃', '&#9731;'],
    \    ['☄', '&#9732;'],
    \    ['★', '&#9733;'],
    \    ['☆', '&#9734;'],
    \    ['☇', '&#9735;'],
    \    ['☈', '&#9736;'],
    \    ['☉', '&#9737;'],
    \    ['☊', '&#9738;'],
    \    ['☋', '&#9739;'],
    \    ['☌', '&#9740;'],
    \    ['☍', '&#9741;'],
    \    ['☎', '&#9742;'],
    \    ['☏', '&#9743;'],
    \    ['☐', '&#9744;'],
    \    ['☑', '&#9745;'],
    \    ['☒', '&#9746;'],
    \    ['☓', '&#9747;'],
    \    ['☚', '&#9754;'],
    \    ['☛', '&#9755;'],
    \    ['☜', '&#9756;'],
    \    ['☝', '&#9757;'],
    \    ['☞', '&#9758;'],
    \    ['☟', '&#9759;'],
    \    ['☠', '&#9760;'],
    \    ['☡', '&#9761;'],
    \    ['☢', '&#9762;'],
    \    ['☣', '&#9763;'],
    \    ['☤', '&#9764;'],
    \    ['☥', '&#9765;'],
    \    ['☦', '&#9766;'],
    \    ['☧', '&#9767;'],
    \    ['☨', '&#9768;'],
    \    ['☩', '&#9769;'],
    \    ['☪', '&#9770;'],
    \    ['☫', '&#9771;'],
    \    ['☬', '&#9772;'],
    \    ['☭', '&#9773;'],
    \    ['☮', '&#9774;'],
    \    ['☯', '&#9775;'],
    \    ['☰', '&#9776;'],
    \    ['☱', '&#9777;'],
    \    ['☲', '&#9778;'],
    \    ['☳', '&#9779;'],
    \    ['☴', '&#9780;'],
    \    ['☵', '&#9781;'],
    \    ['☶', '&#9782;'],
    \    ['☷', '&#9783;'],
    \    ['☸', '&#9784;'],
    \    ['☹', '&#9785;'],
    \    ['☺', '&#9786;'],
    \    ['☻', '&#9787;'],
    \    ['☽', '&#9789;'],
    \    ['☾', '&#9790;'],
    \    ['☿', '&#9791;'],
    \    ['♀', '&#9792;'],
    \    ['♁', '&#9793;'],
    \    ['♂', '&#9794;'],
    \    ['♃', '&#9795;'],
    \    ['♄', '&#9796;'],
    \    ['♅', '&#9797;'],
    \    ['♆', '&#9798;'],
    \    ['♇', '&#9799;'],
    \    ['♈', '&#9800;'],
    \    ['♉', '&#9801;'],
    \    ['♊', '&#9802;'],
    \    ['♋', '&#9803;'],
    \    ['♌', '&#9804;'],
    \    ['♍', '&#9805;'],
    \    ['♎', '&#9806;'],
    \    ['♏', '&#9807;'],
    \    ['♐', '&#9808;'],
    \    ['♑', '&#9809;'],
    \    ['♒', '&#9810;'],
    \    ['♓', '&#9811;'],
    \    ['♔', '&#9812;'],
    \    ['♕', '&#9813;'],
    \    ['♖', '&#9814;'],
    \    ['♗', '&#9815;'],
    \    ['♘', '&#9816;'],
    \    ['♙', '&#9817;'],
    \    ['♚', '&#9818;'],
    \    ['♛', '&#9819;'],
    \    ['♜', '&#9820;'],
    \    ['♝', '&#9821;'],
    \    ['♞', '&#9822;'],
    \    ['♟', '&#9823;'],
    \    ['♠', '&spades;'],
    \    ['♡', '&#9825;'],
    \    ['♢', '&#9826;'],
    \    ['♣', '&clubs;'],
    \    ['♤', '&#9828;'],
    \    ['♥', '&hearts;'],
    \    ['♦', '&diams;'],
    \    ['♧', '&#9831;'],
    \    ['♨', '&#9832;'],
    \    ['♩', '&#9833;'],
    \    ['♪', '&#9834;'],
    \    ['♫', '&#9835;'],
    \    ['♬', '&#9836;'],
    \    ['♭', '&#9837;'],
    \    ['♮', '&#9838;'],
    \    ['♯', '&#9839;'],
    \    ['✁', '&#9985;'],
    \    ['✂', '&#9986;'],
    \    ['✃', '&#9987;'],
    \    ['✄', '&#9988;'],
    \    ['✆', '&#9990;'],
    \    ['✇', '&#9991;'],
    \    ['✈', '&#9992;'],
    \    ['✉', '&#9993;'],
    \    ['✌', '&#9996;'],
    \    ['✍', '&#9997;'],
    \    ['✎', '&#9998;'],
    \    ['✏', '&#9999;'],
    \    ['✓', '&#10003;'],
    \    ['✔', '&#10004;'],
    \    ['✕', '&#100005;'],
    \    ['✖', '&#10006;'],
    \    ['✗', '&#10007;'],
    \    ['✘', '&#10008;'],
    \    ['✝', '&#10013;'],
    \    ['✞', '&#10014;'],
    \    ['✟', '&#10015;'],
    \    ['✠', '&#10016;'],
    \    ['✡', '&#10017;'],
    \    ['❛', '&#10075;'],
    \    ['❜', '&#10076;'],
    \    ['❝', '&#10077;'],
    \    ['❞', '&#10078;'],
    \    ['Α', '&Alpha;'],
    \    ['Β', '&Beta;'],
    \    ['Γ', '&Gamma;'],
    \    ['Δ', '&Delta;'],
    \    ['Ε', '&Epsilon;'],
    \    ['Ζ', '&Zeta;'],
    \    ['Η', '&Eta;'],
    \    ['Θ', '&Theta;'],
    \    ['Ι', '&Iota;'],
    \    ['Κ', '&Kappa;'],
    \    ['Λ', '&Lambda;'],
    \    ['Μ', '&Mu;'],
    \    ['Ν', '&Nu;'],
    \    ['Ξ', '&Xi;'],
    \    ['Ο', '&Omicron;'],
    \    ['Π', '&Pi;'],
    \    ['Ρ', '&Rho;'],
    \    ['Σ', '&Sigma;'],
    \    ['Τ', '&Tau;'],
    \    ['Î¥', '&Upsilon;'],
    \    ['Φ', '&Phi;'],
    \    ['Χ', '&Chi;'],
    \    ['Ψ', '&Psi;'],
    \    ['Ω', '&Omega;'],
    \    ['α', '&alpha;'],
    \    ['β', '&beta;'],
    \    ['γ', '&gamma;'],
    \    ['δ', '&delta;'],
    \    ['ε', '&epsilon;'],
    \    ['ζ', '&zeta;'],
    \    ['η', '&eta;'],
    \    ['θ', '&theta;'],
    \    ['ι', '&iota;'],
    \    ['κ', '&kappa;'],
    \    ['λ', '&lambda;'],
    \    ['μ', '&mu;'],
    \    ['ν', '&nu;'],
    \    ['ξ', '&xi;'],
    \    ['ο', '&omicron;'],
    \    ['π', '&pi;'],
    \    ['ρ', '&rho;'],
    \    ['ς', '&sigmaf;'],
    \    ['σ', '&sigma;'],
    \    ['τ', '&tau;'],
    \    ['υ', '&upsilon;'],
    \    ['φ', '&phi;'],
    \    ['χ', '&chi;'],
    \    ['ψ', '&psi;'],
    \    ['ω', '&omega;'],
    \    ['ϑ', '&thetasym;'],
    \    ['ϒ', '&upsih;'],
    \    ['ϖ', '&piv;']
    \]

    if a:action == 'encode'
        let pat = 0
        let sub = 1
    elseif a:action == 'decode'
        let pat = 1
        let sub = 0
    else
        return
    endif

    for pair in entities
        let substitution = substitute(pair[sub], '&', '\\\&', 'g')
        execute 'silent '.a:firstline.','.a:lastline.'s/'.pair[pat].'/'.substitution.'/eg'
    endfor
endfunction