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PEG4DOT-Notes.html
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PEG4DOT-Notes.html
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<html>
<head>
<meta http-equiv=Content-Type content="text/html; charset=windows-1252">
<title>PEG for GraphViz DOT</title>
<style>
<!--
td {
font-family: monospace;
padding-right: .5em;
}
-->
</style>
</head>
<body lang=EN-US link=blue vlink=purple>
<h1>PEG for GraphViz DOT</h1>
<table border=0 cellspacing=0 cellpadding=0 style='border-collapse:collapse'>
<tr>
<th nowrap></th>
<th nowrap valign=top>
<p>"Abstract Grammar" (year 2020) from<br>
http://www.graphviz.org/doc/info/lang.html</p>
</th>
<th nowrap></th>
<th nowrap valign=top>
<p>Notation converted to PEG.</p>
</th>
<th nowrap></th>
<th nowrap valign=top>
<p>Debugged.</p>
</th>
<th nowrap></th>
<th nowrap valign=top>
<p>Simplification.<br>
Recursion converted to simple repetition <br>
operators.</p>
</th>
<th nowrap></th>
<th nowrap valign=top>
<p>Completion.<br>
Spacing.</p>
</th>
</tr>
<tr>
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</tr>
<tr>
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<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>file <-</p>
</td>
<td nowrap>
<p>_ graph+</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>graph:</p>
</td>
<td nowrap>
<p>[ <b>strict</b> ] (<b>graph</b> | <b>digraph</b>) [ ID ] '{' stmt_list '}'</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>graph <-</p>
</td>
<td nowrap>
<p>'strict'? ('graph' / 'digraph') ID? '{' stmt_list '}'</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>graph <-</p>
</td>
<td nowrap>
<p>'strict'? ('graph' / 'digraph') ID? '{' stmt_list '}'</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>graph <-</p>
</td>
<td nowrap>
<p>'strict'? ('graph' / 'digraph') ID? '{' stmt_list '}'</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>graph <-</p>
</td>
<td nowrap>
<p>('strict' _)? ('graph' / 'digraph') _ ID? '{' _ stmt_list '}' _</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>stmt_list:</p>
</td>
<td nowrap>
<p>[ stmt [ ';' ] stmt_list ]</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>stmt_list <-</p>
</td>
<td nowrap>
<p>(stmt ';'? stmt_list)?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>stmt_list <-</p>
</td>
<td nowrap>
<p>(stmt ';'? stmt_list)?</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'>stmt_list <-</p>
</td>
<td nowrap style='background:yellow;'>
<p>(stmt ';'?)*</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>stmt_list <-</p>
</td>
<td nowrap>
<p>(stmt (';' _)?)*</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>stmt:</p>
</td>
<td nowrap>
<p>node_stmt</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>stmt <-</p>
</td>
<td nowrap>
<p>node_stmt</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'>stmt <-</p>
</td>
<td nowrap style='background:yellow;'>
<p>attr_stmt</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>stmt <-</p>
</td>
<td nowrap>
<p>attr_stmt</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>stmt <-</p>
</td>
<td nowrap>
<p>attr_stmt</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap>
<p>| edge_stmt</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ edge_stmt</p>
</td>
<td nowrap style='background:yellow;'></td>
<td nowrap style='background:yellow;'>
<p>/ edge_stmt</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ edge_stmt</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ edge_stmt</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap>
<p>| attr_stmt</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ attr_stmt</p>
</td>
<td nowrap style='background:yellow;'></td>
<td nowrap style='background:yellow;'>
<p>/ subgraph</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ subgraph</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ subgraph</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap>
<p>| ID '=' ID</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ ID '=' ID</p>
</td>
<td nowrap style='background:yellow;'></td>
<td nowrap style='background:yellow;'>
<p>/ ID '=' ID</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ ID '=' ID</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ ID '=' _ ID</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap>
<p>| subgraph</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ subgraph</p>
</td>
<td nowrap style='background:yellow;'></td>
<td nowrap style='background:yellow;'>
<p>/ node_stmt</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ node_stmt</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ node_stmt</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>attr_stmt:</p>
</td>
<td nowrap>
<p>(<b>graph</b> | <b>node</b> | <b>edge</b>) attr_list</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>attr_stmt <-</p>
</td>
<td nowrap>
<p>('graph' / 'node' / 'edge') attr_list</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>attr_stmt <-</p>
</td>
<td nowrap>
<p>('graph' / 'node' / 'edge') attr_list</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>attr_stmt <-</p>
</td>
<td nowrap>
<p>('graph' / 'node' / 'edge') attr_list</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>attr_stmt <-</p>
</td>
<td nowrap>
<p>('graph' / 'node' / 'edge') _ attr_list</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>attr_list:</p>
</td>
<td nowrap>
<p>'[' [ a_list ] ']' [ attr_list ]</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>attr_list <-</p>
</td>
<td nowrap>
<p>'[' a_list? ']' attr_list?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>attr_list <-</p>
</td>
<td nowrap>
<p>'[' a_list? ']' attr_list?</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'>attr_list <-</p>
</td>
<td nowrap style='background:yellow;'>
<p>('[' attr* ']')+</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>attr_list <-</p>
</td>
<td nowrap>
<p>('[' _ attr* ']' _)+</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>a_list:</p>
</td>
<td nowrap>
<p>ID '=' ID [ (';' | ',') ] [ a_list ]</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>a_list <-</p>
</td>
<td nowrap>
<p>ID '=' ID [;,]? a_list?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>a_list <-</p>
</td>
<td nowrap>
<p>ID '=' ID [;,]? a_list?</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'><s>a_list <-</s></p>
</td>
<td nowrap style='background:yellow;'>
<p><s>(ID '=' ID [;,]?)+</s></p>
</td>
<td nowrap></td>
<td nowrap></td>
</tr>
<tr>
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<td nowrap></td>
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<td nowrap></td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'>attr <-</p>
</td>
<td nowrap style='background:yellow;'>
<p>ID '=' ID [;,]?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>attr <-</p>
</td>
<td nowrap>
<p>ID '=' _ ID ([;,] _)?</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>edge_stmt:</p>
</td>
<td nowrap>
<p>(node_id | subgraph) edgeRHS [ attr_list ]</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>edge_stmt <-</p>
</td>
<td nowrap>
<p>(node_id / subgraph) edgeRHS attr_list?</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'>edge_stmt <-</p>
</td>
<td nowrap style='background:yellow;'>
<p>(subgraph / node_id) edgeRHS attr_list?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>edge_stmt <-</p>
</td>
<td nowrap>
<p>(subgraph / node_id) edgeRHS attr_list?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>edge_stmt <-</p>
</td>
<td nowrap>
<p>(subgraph / node_id) edgeRHS attr_list?</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>edgeRHS:</p>
</td>
<td nowrap>
<p>edgeop (node_id | subgraph) [ edgeRHS ]</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>edgeRHS <-</p>
</td>
<td nowrap>
<p>edgeop (node_id / subgraph) edgeRHS?</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'>edgeRHS <-</p>
</td>
<td nowrap style='background:yellow;'>
<p>edgeop (subgraph / node_id) edgeRHS?</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'>edgeRHS <-</p>
</td>
<td nowrap style='background:yellow;'>
<p>(edgeop (subgraph / node_id))+</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>edgeRHS <-</p>
</td>
<td nowrap>
<p>(edgeop (subgraph / node_id))+</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>node_stmt:</p>
</td>
<td nowrap>
<p>node_id [ attr_list ]</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>node_stmt <-</p>
</td>
<td nowrap>
<p>node_id attr_list?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>node_stmt <-</p>
</td>
<td nowrap>
<p>node_id attr_list?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>node_stmt <-</p>
</td>
<td nowrap>
<p>node_id attr_list?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>node_stmt <-</p>
</td>
<td nowrap>
<p>node_id attr_list?</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>node_id:</p>
</td>
<td nowrap>
<p>ID [ port ]</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>node_id <-</p>
</td>
<td nowrap>
<p>ID port?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>node_id <-</p>
</td>
<td nowrap>
<p>ID port?</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'>node_id <-</p>
</td>
<td nowrap style='background:yellow;'>
<p>ID port? port?</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>node_id <-</p>
</td>
<td nowrap>
<p>ID port? port?</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>port:</p>
</td>
<td nowrap>
<p>':' ID [ ':' compass_pt ]</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>port <-</p>
</td>
<td nowrap>
<p>':' ID (':' compass_pt)?</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'>port <-</p>
</td>
<td nowrap style='background:yellow;'>
<p>':' ID (':' ID)?</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'>port <-</p>
</td>
<td nowrap style='background:yellow;'>
<p>':' ID</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>port <-</p>
</td>
<td nowrap>
<p>':' _ ID</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap>
<p>| ':' compass_pt</p>
</td>
<td nowrap></td>
<td nowrap>
<p>/ ':' compass_pt</p>
</td>
<td nowrap style='background:yellow;'></td>
<td nowrap style='background:yellow;'></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>subgraph:</p>
</td>
<td nowrap>
<p>[ <b>subgraph</b> [ ID ] ] '{' stmt_list '}'</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>subgraph <-</p>
</td>
<td nowrap>
<p>('subgraph' ID?)? '{' stmt_list '}'</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>subgraph <-</p>
</td>
<td nowrap>
<p>('subgraph' ID?)? '{' stmt_list '}'</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>subgraph <-</p>
</td>
<td nowrap>
<p>('subgraph' ID?)? '{' stmt_list '}'</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>subgraph <-</p>
</td>
<td nowrap>
<p>('subgraph' _ ID?)? '{' _ stmt_list '}' _</p>
</td>
</tr>
<tr>
<td nowrap>
<p align=right style='text-align:right'>compass_pt:</p>
</td>
<td nowrap>
<p>(<b>n</b> | <b>ne</b> | <b>e</b> | <b>se</b> | <b>s</b> | <b>sw</b> | <b>w</b> | <b>nw</b> | <b>c</b> | <b>_</b>)</p>
</td>
<td nowrap>
<p align=right style='text-align:right'>compass_pt <-</p>
</td>
<td nowrap>
<p>'n' / 'ne' / 'e' / 'se' / 's' / 'sw' / 'w' / 'nw' / 'c' / '_'</p>
</td>
<td nowrap style='background:yellow;'>
<p align=right style='text-align:right'><s>compass_pt <-</s></p>
</td>
<td nowrap style='background:yellow;'>
<p><s>'ne' / 'nw' / 'se' / 'sw'/ 's' / 'w' / 'n' / 'e' / 'c' / '_'</s></p>
</td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>edgeop <-</p>
</td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>edgeop <-</p>
</td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>edgeop <-</p>
</td>
<td nowrap>
<p>('--' / '->') _</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>ID <-</p>
</td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>ID <-</p>
</td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>ID <-</p>
</td>
<td nowrap>
<p> HTML</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p>/ QUOTED</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p>/ NUMERAL</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p>/ STRING</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>HTML <-</p>
</td>
<td nowrap>
<p>'<' (![<>] . / HTML)* '>' _</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>QUOTED <-</p>
</td>
<td nowrap>
<p>'"' ESCAPED* '"' _ ('+' _ '"' ESCAPED* '"' _)*</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>ESCAPED <-</p>
</td>
<td nowrap>
<p>ESC_QUOTE</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p>/ ESC_EOL</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p>/ '\\' .</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p>/ !'"' .</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>ESC_QUOTE <-</p>
</td>
<td nowrap>
<p>'\\"'</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>ESC_EOL <-</p>
</td>
<td nowrap>
<p>'\\' EOL</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>NUMERAL <-</p>
</td>
<td nowrap>
<p>'-'? ([0-9]+ ('.' [0-9]*)? / '.' [0-9]+) _</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>STRING <-</p>
</td>
<td nowrap>
<p>[A-Z_a-z\u0080-\uFFFF] [0-9A-Z_a-z\u0080-\uFFFF]* _</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>_ <-</p>
</td>
<td nowrap>
<p>([ \t] / EOL / COMMENT)*</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>COMMENT <-</p>
</td>
<td nowrap>
<p>COMMENT_HASH</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p>/ COMMENT_SLASH</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p>/ COMMENT_BLOCK</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>COMMENT_HASH <-</p>
</td>
<td nowrap>
<p>'#' (!EOL .)*</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>COMMENT_SLASH <-</p>
</td>
<td nowrap>
<p>'//' (!EOL .)*</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>COMMENT_BLOCK <-</p>
</td>
<td nowrap>
<p>'/*' (!'*/' .)* '*/'</p>
</td>
</tr>
<tr>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap></td>
<td nowrap>
<p align=right style='text-align:right'>EOL <-</p>
</td>
<td nowrap>
<p>'\r\n' / '\n' / '\r'</p>
</td>
</tr>
</table>
<h2>Notes</h2>
<p>Main DOT specification:</p>
<p>The keywords <b>node</b>, <b>edge</b>, <b>graph</b>, <b>digraph</b>, <b>subgraph</b>,
and <b>strict</b> <s>are case-independent</s>. <i>At least in GraphViz
2.38 and 2.46 keywords are case sensitive! So attribute statement with
"Node" keyword will create a new node (will be interpreted as node
statement)!</i></p>
<p>As another aid for readability, dot allows double-quoted strings
to span multiple physical lines using the standard C convention of a backslash
immediately preceding a newline character. (<i>In GraphViz 2.38 this is true,
but in 2.46 newline characters are ignored also if not escaped! Seems like a bug
because it breaks HTML strings (that preserve them) and quoted strings
equivalence.</i>)</p>
<p>In quoted strings in DOT, the <s>only</s> escaped character
is double-quote ("). That is, in quoted strings, the dyad \" is
converted to "; <s>all other characters are left unchanged</s>. (<i>As
stated above - backslash before newline character removes them both.</i>) In
particular, \\ remains \\. Layout engines may apply additional escape
sequences.<br>
<a href="http://www.graphviz.org/doc/info/lang.html">http://www.graphviz.org/doc/info/lang.html</a><br>
<a href="https://gitlab.com/graphviz/graphviz/-/blob/master/doc/info/lang.html">https://gitlab.com/graphviz/graphviz/-/blob/master/doc/info/lang.html</a><br>
<a href="https://gitlab.com/graphviz/graphviz/-/blob/master/doc/infosrc/grammar">https://gitlab.com/graphviz/graphviz/-/blob/master/doc/infosrc/grammar</a></p>
<hr>
<p>Note that it is legal to have a portname the same as one of
the compass points. In this case, this reference will be resolved to the port.</p>
<p><i>Contrary to specification compass points type is ID!</i><br>
<a href="http://www.graphviz.org/doc/info/attrs.html#k:portPos">http://www.graphviz.org/doc/info/attrs.html#k:portPos</a><br>
graphviz-2.46.0/lib/common/shapes.c compassPort()</p>