HCoop / hcoop / debian / mlton.git / blame
| Commit | Line | Data |
|---|---|---|
| 7f918cf1 CE |
1 | <!DOCTYPE html>\r |
| 2 | <html lang="en">\r | |
| 3 | <head>\r | |
| 4 | <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">\r | |
| 5 | <meta name="generator" content="AsciiDoc 8.6.9">\r | |
| 6 | <title>ShowBasis</title>\r | |
| 7 | <link rel="stylesheet" href="./asciidoc.css" type="text/css">\r | |
| 8 | <link rel="stylesheet" href="./pygments.css" type="text/css">\r | |
| 9 | \r | |
| 10 | \r | |
| 11 | <script type="text/javascript" src="./asciidoc.js"></script>\r | |
| 12 | <script type="text/javascript">\r | |
| 13 | /*<![CDATA[*/\r | |
| 14 | asciidoc.install();\r | |
| 15 | /*]]>*/\r | |
| 16 | </script>\r | |
| 17 | <link rel="stylesheet" href="./mlton.css" type="text/css">\r | |
| 18 | </head>\r | |
| 19 | <body class="article">\r | |
| 20 | <div id="banner">\r | |
| 21 | <div id="banner-home">\r | |
| 22 | <a href="./Home">MLton 20180207</a>\r | |
| 23 | </div>\r | |
| 24 | </div>\r | |
| 25 | <div id="header">\r | |
| 26 | <h1>ShowBasis</h1>\r | |
| 27 | </div>\r | |
| 28 | <div id="content">\r | |
| 29 | <div id="preamble">\r | |
| 30 | <div class="sectionbody">\r | |
| 31 | <div class="paragraph"><p>MLton has a flag, <span class="monospaced">-show-basis <file></span>, that causes MLton to pretty\r | |
| 32 | print to <em>file</em> the basis defined by the input program. For example,\r | |
| 33 | if <span class="monospaced">foo.sml</span> contains</p></div>\r | |
| 34 | <div class="listingblock">\r | |
| 35 | <div class="content"><div class="highlight"><pre><span class="k">fun</span><span class="w"> </span><span class="n">f</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="n">+</span><span class="w"> </span><span class="mi">1</span><span class="w"></span>\r | |
| 36 | </pre></div></div></div>\r | |
| 37 | <div class="paragraph"><p>then <span class="monospaced">mlton -show-basis foo.basis foo.sml</span> will create <span class="monospaced">foo.basis</span>\r | |
| 38 | with the following contents.</p></div>\r | |
| 39 | <div class="listingblock">\r | |
| 40 | <div class="content monospaced">\r | |
| 41 | <pre>val f: int -> int</pre>\r | |
| 42 | </div></div>\r | |
| 43 | <div class="paragraph"><p>If you only want to see the basis and do not wish to compile the\r | |
| 44 | program, you can call MLton with <span class="monospaced">-stop tc</span>.</p></div>\r | |
| 45 | </div>\r | |
| 46 | </div>\r | |
| 47 | <div class="sect1">\r | |
| 48 | <h2 id="_displaying_signatures">Displaying signatures</h2>\r | |
| 49 | <div class="sectionbody">\r | |
| 50 | <div class="paragraph"><p>When displaying signatures, MLton prefixes types defined in the\r | |
| 51 | signature them with <span class="monospaced">_sig.</span> to distinguish them from types defined in the\r | |
| 52 | environment. For example,</p></div>\r | |
| 53 | <div class="listingblock">\r | |
| 54 | <div class="content"><div class="highlight"><pre><span class="k">signature</span><span class="w"> </span><span class="n">SIG</span><span class="w"> </span><span class="p">=</span><span class="w"></span>\r | |
| 55 | <span class="w"> </span><span class="k">sig</span><span class="w"></span>\r | |
| 56 | <span class="w"> </span><span class="k">type</span><span class="w"> </span><span class="n">t</span><span class="w"></span>\r | |
| 57 | <span class="w"> </span><span class="k">val</span><span class="w"> </span><span class="n">x</span><span class="p">:</span><span class="w"> </span><span class="n">t</span><span class="w"> </span><span class="n">*</span><span class="w"> </span><span class="n">int</span><span class="w"> </span><span class="p">-></span><span class="w"> </span><span class="n">unit</span><span class="w"></span>\r | |
| 58 | <span class="w"> </span><span class="k">end</span><span class="w"></span>\r | |
| 59 | </pre></div></div></div>\r | |
| 60 | <div class="paragraph"><p>is displayed as</p></div>\r | |
| 61 | <div class="listingblock">\r | |
| 62 | <div class="content monospaced">\r | |
| 63 | <pre>signature SIG =\r | |
| 64 | sig\r | |
| 65 | type t\r | |
| 66 | val x: _sig.t * int -> unit\r | |
| 67 | end</pre>\r | |
| 68 | </div></div>\r | |
| 69 | <div class="paragraph"><p>Notice that <span class="monospaced">int</span> occurs without the <span class="monospaced">_sig.</span> prefix.</p></div>\r | |
| 70 | <div class="paragraph"><p>MLton also uses a canonical name for each type in the signature, and\r | |
| 71 | that name is used everywhere for that type, no matter what the input\r | |
| 72 | signature looked like. For example:</p></div>\r | |
| 73 | <div class="listingblock">\r | |
| 74 | <div class="content"><div class="highlight"><pre><span class="k">signature</span><span class="w"> </span><span class="n">SIG</span><span class="w"> </span><span class="p">=</span><span class="w"></span>\r | |
| 75 | <span class="w"> </span><span class="k">sig</span><span class="w"></span>\r | |
| 76 | <span class="w"> </span><span class="k">type</span><span class="w"> </span><span class="n">t</span><span class="w"></span>\r | |
| 77 | <span class="w"> </span><span class="k">type</span><span class="w"> </span><span class="n">u</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">t</span><span class="w"></span>\r | |
| 78 | <span class="w"> </span><span class="k">val</span><span class="w"> </span><span class="n">x</span><span class="p">:</span><span class="w"> </span><span class="n">t</span><span class="w"></span>\r | |
| 79 | <span class="w"> </span><span class="k">val</span><span class="w"> </span><span class="n">y</span><span class="p">:</span><span class="w"> </span><span class="n">u</span><span class="w"></span>\r | |
| 80 | <span class="w"> </span><span class="k">end</span><span class="w"></span>\r | |
| 81 | </pre></div></div></div>\r | |
| 82 | <div class="paragraph"><p>is displayed as</p></div>\r | |
| 83 | <div class="listingblock">\r | |
| 84 | <div class="content monospaced">\r | |
| 85 | <pre>signature SIG =\r | |
| 86 | sig\r | |
| 87 | type t\r | |
| 88 | type u = _sig.t\r | |
| 89 | val x: _sig.t\r | |
| 90 | val y: _sig.t\r | |
| 91 | end</pre>\r | |
| 92 | </div></div>\r | |
| 93 | <div class="paragraph"><p>Canonical names are always relative to the "top" of the signature,\r | |
| 94 | even when used in nested substructures. For example:</p></div>\r | |
| 95 | <div class="listingblock">\r | |
| 96 | <div class="content"><div class="highlight"><pre><span class="k">signature</span><span class="w"> </span><span class="n">S</span><span class="w"> </span><span class="p">=</span><span class="w"></span>\r | |
| 97 | <span class="w"> </span><span class="k">sig</span><span class="w"></span>\r | |
| 98 | <span class="w"> </span><span class="k">type</span><span class="w"> </span><span class="n">t</span><span class="w"></span>\r | |
| 99 | <span class="w"> </span><span class="k">val</span><span class="w"> </span><span class="n">w</span><span class="p">:</span><span class="w"> </span><span class="n">t</span><span class="w"></span>\r | |
| 100 | <span class="w"> </span><span class="k">structure</span><span class="w"> </span><span class="n">U</span><span class="p">:</span><span class="w"></span>\r | |
| 101 | <span class="w"> </span><span class="k">sig</span><span class="w"></span>\r | |
| 102 | <span class="w"> </span><span class="k">type</span><span class="w"> </span><span class="n">u</span><span class="w"></span>\r | |
| 103 | <span class="w"> </span><span class="k">val</span><span class="w"> </span><span class="n">x</span><span class="p">:</span><span class="w"> </span><span class="n">t</span><span class="w"></span>\r | |
| 104 | <span class="w"> </span><span class="k">val</span><span class="w"> </span><span class="n">y</span><span class="p">:</span><span class="w"> </span><span class="n">u</span><span class="w"></span>\r | |
| 105 | <span class="w"> </span><span class="k">end</span><span class="w"></span>\r | |
| 106 | <span class="w"> </span><span class="k">val</span><span class="w"> </span><span class="n">z</span><span class="p">:</span><span class="w"> </span><span class="n">U</span><span class="p">.</span><span class="n">u</span><span class="w"></span>\r | |
| 107 | <span class="w"> </span><span class="k">end</span><span class="w"></span>\r | |
| 108 | </pre></div></div></div>\r | |
| 109 | <div class="paragraph"><p>is displayed as</p></div>\r | |
| 110 | <div class="listingblock">\r | |
| 111 | <div class="content monospaced">\r | |
| 112 | <pre>signature S =\r | |
| 113 | sig\r | |
| 114 | type t\r | |
| 115 | val w: _sig.t\r | |
| 116 | val z: _sig.U.u\r | |
| 117 | structure U:\r | |
| 118 | sig\r | |
| 119 | type u\r | |
| 120 | val x: _sig.t\r | |
| 121 | val y: _sig.U.u\r | |
| 122 | end\r | |
| 123 | end</pre>\r | |
| 124 | </div></div>\r | |
| 125 | </div>\r | |
| 126 | </div>\r | |
| 127 | <div class="sect1">\r | |
| 128 | <h2 id="_displaying_structures">Displaying structures</h2>\r | |
| 129 | <div class="sectionbody">\r | |
| 130 | <div class="paragraph"><p>When displaying structures, MLton uses signature constraints wherever\r | |
| 131 | possible, combined with <span class="monospaced">where type</span> clauses to specify the meanings\r | |
| 132 | of the types defined within the signature. For example:</p></div>\r | |
| 133 | <div class="listingblock">\r | |
| 134 | <div class="content"><div class="highlight"><pre><span class="k">signature</span><span class="w"> </span><span class="n">SIG</span><span class="w"> </span><span class="p">=</span><span class="w"></span>\r | |
| 135 | <span class="w"> </span><span class="k">sig</span><span class="w"></span>\r | |
| 136 | <span class="w"> </span><span class="k">type</span><span class="w"> </span><span class="n">t</span><span class="w"></span>\r | |
| 137 | <span class="w"> </span><span class="k">val</span><span class="w"> </span><span class="n">x</span><span class="p">:</span><span class="w"> </span><span class="n">t</span><span class="w"></span>\r | |
| 138 | <span class="w"> </span><span class="k">end</span><span class="w"></span>\r | |
| 139 | <span class="k">structure</span><span class="w"> </span><span class="n">S</span><span class="p">:</span><span class="w"> </span><span class="n">SIG</span><span class="w"> </span><span class="p">=</span><span class="w"></span>\r | |
| 140 | <span class="w"> </span><span class="k">struct</span><span class="w"></span>\r | |
| 141 | <span class="w"> </span><span class="k">type</span><span class="w"> </span><span class="n">t</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">int</span><span class="w"></span>\r | |
| 142 | <span class="w"> </span><span class="k">val</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="mi">13</span><span class="w"></span>\r | |
| 143 | <span class="w"> </span><span class="k">end</span><span class="w"></span>\r | |
| 144 | <span class="k">structure</span><span class="w"> </span><span class="n">S2</span><span class="p">:></span><span class="w"> </span><span class="n">SIG</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">S</span><span class="w"></span>\r | |
| 145 | </pre></div></div></div>\r | |
| 146 | <div class="paragraph"><p>is displayed as</p></div>\r | |
| 147 | <div class="listingblock">\r | |
| 148 | <div class="content monospaced">\r | |
| 149 | <pre>signature SIG =\r | |
| 150 | sig\r | |
| 151 | type t\r | |
| 152 | val x: _sig.t\r | |
| 153 | end\r | |
| 154 | structure S: SIG\r | |
| 155 | where type t = int\r | |
| 156 | structure S2: SIG\r | |
| 157 | where type t = S2.t</pre>\r | |
| 158 | </div></div>\r | |
| 159 | </div>\r | |
| 160 | </div>\r | |
| 161 | </div>\r | |
| 162 | <div id="footnotes"><hr></div>\r | |
| 163 | <div id="footer">\r | |
| 164 | <div id="footer-text">\r | |
| 165 | </div>\r | |
| 166 | <div id="footer-badges">\r | |
| 167 | </div>\r | |
| 168 | </div>\r | |
| 169 | </body>\r | |
| 170 | </html>\r |