about summary refs log tree commit diff
path: root/src/libexpr/lexer.l
blob: df30a5ed07133d135d51d300b0a246126fab5916 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
%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);
}

}