diff options
Diffstat (limited to 'src/libexpr/lexer.l')
| -rw-r--r-- | src/libexpr/lexer.l | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/src/libexpr/lexer.l b/src/libexpr/lexer.l new file mode 100644 index 000000000000..82520ee7a59a --- /dev/null +++ b/src/libexpr/lexer.l @@ -0,0 +1,193 @@ +%option reentrant bison-bridge bison-locations +%option noyywrap +%option never-interactive + + +%x STRING +%x IND_STRING + + +%{ +#include "nixexpr.hh" +#include "parser-tab.hh" + +using namespace nix; + +namespace nix { + + +static void initLoc(YYLTYPE * loc) +{ + loc->first_line = loc->last_line = 1; + loc->first_column = loc->last_column = 1; +} + + +static void adjustLoc(YYLTYPE * loc, const char * s, size_t len) +{ + loc->first_line = loc->last_line; + loc->first_column = loc->last_column; + + while (len--) { + switch (*s++) { + case '\r': + if (*s == '\n') /* cr/lf */ + s++; + /* fall through */ + case '\n': + ++loc->last_line; + loc->last_column = 1; + break; + default: + ++loc->last_column; + } + } +} + + +static Expr * unescapeStr(SymbolTable & symbols, 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 new ExprString(symbols.create(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\.\_\-\+]+)+ +SPATH \<[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; } +or { return OR_KW; } +\.\.\. { return ELLIPSIS; } + +\=\= { return EQ; } +\!\= { return NEQ; } +\<\= { return LEQ; } +\>\= { return GEQ; } +\&\& { return AND; } +\|\| { return OR; } +\-\> { return IMPL; } +\/\/ { return UPDATE; } +\+\+ { return CONCAT; } + +{ID} { yylval->id = strdup(yytext); return ID; } +{INT} { errno = 0; + yylval->n = strtol(yytext, 0, 10); + if (errno != 0) + throw ParseError(format("invalid integer ‘%1%’") % yytext); + return INT; + } + +\$\{ { return DOLLAR_CURLY; } + +\" { 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->e = unescapeStr(data->symbols, yytext); + return STR; + } +<STRING>\$\{ { BEGIN(INITIAL); return DOLLAR_CURLY; } +<STRING>\" { BEGIN(INITIAL); return '"'; } +<STRING>. return yytext[0]; /* just in case: shouldn't be reached */ + +\'\'(\ *\n)? { BEGIN(IND_STRING); return IND_STRING_OPEN; } +<IND_STRING>([^\$\']|\$[^\{\']|\'[^\'\$])+ { + yylval->e = new ExprIndStr(yytext); + return IND_STR; + } +<IND_STRING>\'\'\$ { + yylval->e = new ExprIndStr("$"); + return IND_STR; + } +<IND_STRING>\'\'\' { + yylval->e = new ExprIndStr("''"); + return IND_STR; + } +<IND_STRING>\'\'\\. { + yylval->e = unescapeStr(data->symbols, yytext + 2); + return IND_STR; + } +<IND_STRING>\$\{ { BEGIN(INITIAL); return DOLLAR_CURLY; } +<IND_STRING>\'\' { BEGIN(INITIAL); return IND_STRING_CLOSE; } +<IND_STRING>\' { + yylval->e = new ExprIndStr("'"); + return IND_STR; + } +<IND_STRING>. return yytext[0]; /* just in case: shouldn't be reached */ + +{PATH} { yylval->path = strdup(yytext); return PATH; } +{SPATH} { yylval->path = strdup(yytext); return SPATH; } +{URI} { yylval->uri = strdup(yytext); return URI; } + +[ \t\r\n]+ /* eat up whitespace */ +\#[^\r\n]* /* single-line comments */ +\/\*([^*]|\*[^\/])*\*\/ /* long comments */ + +. return yytext[0]; + + +%% + + +namespace nix { + +/* Horrible, disgusting hack: allow the parser to set the scanner + start condition back to STRING. Necessary in interpolations like + "foo${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); +} + +void backToIndString(yyscan_t scanner) +{ + struct yyguts_t * yyg = (struct yyguts_t *) scanner; + BEGIN(IND_STRING); +} + +} |