Sig: Ejemplo en Jison: Calculadora Sup: Análisis Sintáctico Ascendente en Ant: Conceptos Básicos para el Con:
Ind:
Ind:
%%
S : A
;
A : /* empty */
| A x
;
[~/jison/examples/basic2_lex(develop)]$ cat basic2_lex.jison
/* description: Basic grammar that contains a nullable A nonterminal. */
%lex
%%
\s+ {/* skip whitespace */}
[a-zA-Z_]\w* {return 'x';}
/lex
%%
S : A
{ return $1+" identifiers"; }
;
A : /* empty */
{
console.log("starting");
$$ = 0;
}
| A x {
$$ = $1 + 1;
console.log($$)
}
;
$ cat basic2_lex.html
<!DOCTYPE HTML>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Jison</title>
<link rel="stylesheet" href="global.css" type="text/css" media="screen" charset="utf-8" />
</head>
<body>
<h1>basic2_lex demo</h1>
<div id="content">
<script src="jquery/jquery.js"></script>
<script src="basic2_lex.js"></script>
<script src="main.js"></script>
<p>
<input type="text" value="x x x x" /> <button>parse</button>
<span id="output"></span> <!-- Output goes here! -->
</p>
</div>
</body>
</html>
$ cat Rakefile
# install package:
# sudo npm install beautifier
#
# more about beautifier:
# https://github.com/rickeyski/node-beautifier
dec "compile the grammar basic2_lex_ugly.jison"
task :default => %w{basic2_lex_ugly.js} do
sh "mv basic2_lex.js basic2_lex_ugly.js"
sh "jsbeautify basic2_lex_ugly.js > basic2_lex.js"
sh "rm -f basic2_lex_ugly.js"
end
file "basic2_lex_ugly.js" => %w{basic2_lex.jison} do
sh "jison basic2_lex.jison -o basic2_lex.js"
end
[~/jison/examples/basic2_lex(develop)]$ cat global.css
html *
{
font-size: large;
/* The !important ensures that nothing can override what you've set in this style (unless it is also important). */
font-family: Arial;
}
.thumb {
height: 75px;
border: 1px solid #000;
margin: 10px 5px 0 0;
}
h1 { text-align: center; font-size: x-large; }
th, td { vertical-align: top; text-align: left; }
/* #finaltable * { color: white; background-color: black; } */
/* #finaltable table { border-collapse:collapse; } */
/* #finaltable table, td { border:1px solid white; } */
#finaltable:hover td { background-color: blue; }
tr:nth-child(odd) { background-color:#eee; }
tr:nth-child(even) { background-color:#00FF66; }
input { text-align: right; border: none; } /* Align input to the right */
textarea { border: outset; border-color: white; }
table { border: inset; border-color: white; }
.hidden { display: none; }
.unhidden { display: block; }
table.center { margin-left:auto; margin-right:auto; }
#result { border-color: red; }
tr.error { background-color: red; }
pre.output { background-color: white; }
span.repeated { background-color: red }
span.header { background-color: blue }
span.comments { background-color: orange }
span.blanks { background-color: green }
span.nameEqualValue { background-color: cyan }
span.error { background-color: red }
body
{
background-color:#b0c4de; /* blue */
}
ID = NUM separadas
por puntos y comas, por ejemplo a = 4; b = 4.56; c = -8.57e34.
El analizador retorna un hash/objeto
cuyas claves son los identificadores y cuyos valores
son los números.
Clone el repositorio en
https://github.com/crguezl/jison-basic2.
Modifique los analizadores léxico y sintáctico de forma conveniente.
Añada acciones semánticas para que el analizador devuelva una tabla de símbolos con los identificadores y sus valores.