nix-super/src/libexpr/lexer.l

151 lines
3.5 KiB
Text

%option reentrant bison-bridge bison-locations
%option noyywrap
%option never-interactive
%x STRING
%{
#include "aterm.hh"
#include "nixexpr.hh"
#include "nixexpr-ast.hh"
#define BISON_HEADER_HACK
#include "parser-tab.hh"
using namespace nix;
namespace nix {
static void initLoc(YYLTYPE * loc)
{
loc->first_line = 1;
loc->first_column = 1;
}
static void adjustLoc(YYLTYPE * loc, const char * s, size_t len)
{
while (len--) {
switch (*s++) {
case '\r':
if (*s == '\n') /* cr/lf */
s++;
/* fall through */
case '\n':
++loc->first_line;
loc->first_column = 1;
break;
default:
++loc->first_column;
}
}
}
static Expr unescapeStr(const char * s)
{
string t;
char c;
while ((c = *s++)) {
if (c == '\\') {
assert(*s);
c = *s++;
if (c == 'n') t += '\n';
else if (c == 'r') t += '\r';
else if (c == 't') t += '\t';
else t += c;
}
else if (c == '\r') {
/* Normalise CR and CR/LF into LF. */
t += '\n';
if (*s == '\n') s++; /* cr/lf */
}
else t += c;
}
return makeStr(toATerm(t));
}
}
#define YY_USER_INIT initLoc(yylloc)
#define YY_USER_ACTION adjustLoc(yylloc, yytext, yyleng);
%}
ID [a-zA-Z\_][a-zA-Z0-9\_\']*
INT [0-9]+
PATH [a-zA-Z0-9\.\_\-\+]*(\/[a-zA-Z0-9\.\_\-\+]+)+
URI [a-zA-Z][a-zA-Z0-9\+\-\.]*\:[a-zA-Z0-9\%\/\?\:\@\&\=\+\$\,\-\_\.\!\~\*\']+
%%
if { return IF; }
then { return THEN; }
else { return ELSE; }
assert { return ASSERT; }
with { return WITH; }
let { return LET; }
in { return IN; }
rec { return REC; }
inherit { return INHERIT; }
\=\= { return EQ; }
\!\= { return NEQ; }
\&\& { return AND; }
\|\| { return OR; }
\-\> { return IMPL; }
\/\/ { return UPDATE; }
\+\+ { return CONCAT; }
{ID} { yylval->t = toATerm(yytext); return ID; /* !!! alloc */ }
{INT} { int n = atoi(yytext); /* !!! overflow */
yylval->t = ATmake("<int>", n);
return INT;
}
\" { BEGIN(STRING); return '"'; }
<STRING>([^\$\"\\]|\$[^\{\"]|\\.)+ {
/* !!! Not quite right: we want a follow restriction on "$", it
shouldn't be followed by a "{". Right now "$\"" will be consumed
as part of a string, rather than a "$" followed by the string
terminator. Disallow "$\"" for now. */
yylval->t = unescapeStr(yytext); /* !!! alloc */
return STR;
}
<STRING>\$\{ { BEGIN(INITIAL); return DOLLAR_CURLY; }
<STRING>\" { BEGIN(INITIAL); return '"'; }
<STRING>. return yytext[0]; /* just in case: shouldn't be reached */
{PATH} { yylval->t = toATerm(yytext); return PATH; /* !!! alloc */ }
{URI} { yylval->t = toATerm(yytext); return URI; /* !!! alloc */ }
[ \t\r\n]+ /* eat up whitespace */
\#[^\r\n]* /* single-line comments */
\/\*([^*]|\*[^\/])*\*\/ /* long comments */
. return yytext[0];
%%
namespace nix {
/* Horrible, disgusting hack: allow the parser to set the scanner
start condition back to STRING. Necessary in interpolations like
"foo${expr}bar"; after the close brace we have to go back to the
STRING state. */
void backToString(yyscan_t scanner)
{
struct yyguts_t * yyg = (struct yyguts_t *) scanner;
BEGIN(STRING);
}
}