diff options
Diffstat (limited to 'third_party/nix/src/libexpr/lexer.l')
| -rw-r--r-- | third_party/nix/src/libexpr/lexer.l | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/third_party/nix/src/libexpr/lexer.l b/third_party/nix/src/libexpr/lexer.l new file mode 100644 index 0000000000..c34e5c3839 --- /dev/null +++ b/third_party/nix/src/libexpr/lexer.l @@ -0,0 +1,222 @@ +%option reentrant bison-bridge bison-locations +%option noyywrap +%option never-interactive +%option stack +%option nodefault +%option nounput noyy_top_state + + +%s DEFAULT +%x STRING +%x IND_STRING + + +%{ +#include <boost/lexical_cast.hpp> + +#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, size_t length) +{ + string t; + t.reserve(length); + 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); + +#define PUSH_STATE(state) yy_push_state(state, yyscanner) +#define POP_STATE() yy_pop_state(yyscanner) + +%} + + +ANY .|\n +ID [a-zA-Z\_][a-zA-Z0-9\_\'\-]* +INT [0-9]+ +FLOAT (([1-9][0-9]*\.[0-9]*)|(0?\.[0-9]+))([Ee][+-]?[0-9]+)? +PATH [a-zA-Z0-9\.\_\-\+]*(\/[a-zA-Z0-9\.\_\-\+]+)+\/? +HPATH \~(\/[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; + try { + yylval->n = boost::lexical_cast<int64_t>(yytext); + } catch (const boost::bad_lexical_cast &) { + throw ParseError(format("invalid integer '%1%'") % yytext); + } + return INT; + } +{FLOAT} { errno = 0; + yylval->nf = strtod(yytext, 0); + if (errno != 0) + throw ParseError(format("invalid float '%1%'") % yytext); + return FLOAT; + } + +\$\{ { PUSH_STATE(DEFAULT); return DOLLAR_CURLY; } + +\} { /* State INITIAL only exists at the bottom of the stack and is + used as a marker. DEFAULT replaces it everywhere else. + Popping when in INITIAL state causes an empty stack exception, + so don't */ + if (YYSTATE != INITIAL) + POP_STATE(); + return '}'; + } +\{ { PUSH_STATE(DEFAULT); return '{'; } + +\" { PUSH_STATE(STRING); return '"'; } +<STRING>([^\$\"\\]|\$[^\{\"\\]|\\{ANY}|\$\\{ANY})*\$/\" | +<STRING>([^\$\"\\]|\$[^\{\"\\]|\\{ANY}|\$\\{ANY})+ { + /* It is impossible to match strings ending with '$' with one + regex because trailing contexts are only valid at the end + of a rule. (A sane but undocumented limitation.) */ + yylval->e = unescapeStr(data->symbols, yytext, yyleng); + return STR; + } +<STRING>\$\{ { PUSH_STATE(DEFAULT); return DOLLAR_CURLY; } +<STRING>\" { POP_STATE(); return '"'; } +<STRING>\$|\\|\$\\ { + /* This can only occur when we reach EOF, otherwise the above + (...|\$[^\{\"\\]|\\.|\$\\.)+ would have triggered. + This is technically invalid, but we leave the problem to the + parser who fails with exact location. */ + return STR; + } + +\'\'(\ *\n)? { PUSH_STATE(IND_STRING); return IND_STRING_OPEN; } +<IND_STRING>([^\$\']|\$[^\{\']|\'[^\'\$])+ { + yylval->e = new ExprIndStr(yytext); + return IND_STR; + } +<IND_STRING>\'\'\$ | +<IND_STRING>\$ { + yylval->e = new ExprIndStr("$"); + return IND_STR; + } +<IND_STRING>\'\'\' { + yylval->e = new ExprIndStr("''"); + return IND_STR; + } +<IND_STRING>\'\'\\{ANY} { + yylval->e = unescapeStr(data->symbols, yytext + 2, yyleng - 2); + return IND_STR; + } +<IND_STRING>\$\{ { PUSH_STATE(DEFAULT); return DOLLAR_CURLY; } +<IND_STRING>\'\' { POP_STATE(); return IND_STRING_CLOSE; } +<IND_STRING>\' { + yylval->e = new ExprIndStr("'"); + return IND_STR; + } + + +{PATH} { if (yytext[yyleng-1] == '/') + throw ParseError("path '%s' has a trailing slash", yytext); + yylval->path = strdup(yytext); + return PATH; + } +{HPATH} { if (yytext[yyleng-1] == '/') + throw ParseError("path '%s' has a trailing slash", yytext); + yylval->path = strdup(yytext); + return HPATH; + } +{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 */ + +{ANY} { + /* Don't return a negative number, as this will cause + Bison to stop parsing without an error. */ + return (unsigned char) yytext[0]; + } + +%% + |