37d7abd694
The expression `with E1; E2' evaluates to E2 with all bindings in
the attribute set E1 substituted. E.g.,
with {x = 123;}; x
evaluates to 123. That is, the attribute set E1 is in scope in E2.
This is particularly useful when importing files containing lots
definitions. E.g., instead of
let {
inherit (import ./foo.nix) a b c d e f;
body = ... a ... f ...;
}
we can now say
with import ./foo.nix;
... a ... f ...
I.e., we don't have to say what variables should be brought into scope.
84 lines
2 KiB
Text
84 lines
2 KiB
Text
%option reentrant bison-bridge bison-locations
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%option noyywrap
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%option never-interactive
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%{
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#include <string.h>
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#include <aterm2.h>
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#include "parser-tab.h"
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static void initLoc(YYLTYPE * loc)
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{
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loc->first_line = 1;
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loc->first_column = 1;
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}
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static void adjustLoc(YYLTYPE * loc, const char * s, size_t len)
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{
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while (len--) {
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switch (*s++) {
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case '\n':
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++loc->first_line;
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loc->first_column = 1;
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break;
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default:
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++loc->first_column;
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}
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}
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}
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#define YY_USER_INIT initLoc(yylloc)
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#define YY_USER_ACTION adjustLoc(yylloc, yytext, yyleng);
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%}
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ID [a-zA-Z\_][a-zA-Z0-9\_\']*
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INT [0-9]+
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STR \"[^\n\"]*\"
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PATH [a-zA-Z0-9\.\_\-\+]*(\/[a-zA-Z0-9\.\_\-\+]+)+
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URI [a-zA-Z][a-zA-Z0-9\+\-\.]*\:[a-zA-Z0-9\%\/\?\:\@\&\=\+\$\,\-\_\.\!\~\*\']+
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%%
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if { return IF; }
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then { return THEN; }
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else { return ELSE; }
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assert { return ASSERT; }
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with { return WITH; }
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let { return LET; }
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rec { return REC; }
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inherit { return INHERIT; }
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\=\= { return EQ; }
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\!\= { return NEQ; }
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\&\& { return AND; }
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\|\| { return OR; }
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\-\> { return IMPL; }
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\/\/ { return UPDATE; }
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{ID} { yylval->t = ATmake("<str>", yytext); return ID; /* !!! alloc */ }
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{INT} { int n = atoi(yytext); /* !!! overflow */
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yylval->t = ATmake("<int>", n);
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return INT;
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}
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{STR} { int len = strlen(yytext);
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yytext[len - 1] = 0;
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yylval->t = ATmake("<str>", yytext + 1);
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yytext[len - 1] = '\"';
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return STR; /* !!! alloc */
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}
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{PATH} { yylval->t = ATmake("<str>", yytext); return PATH; /* !!! alloc */ }
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{URI} { yylval->t = ATmake("<str>", yytext); return URI; /* !!! alloc */ }
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[ \t\n]+ /* eat up whitespace */
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\#[^\n]* /* single-line comments */
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\/\*(.|\n)*\*\/ /* long comments */
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. return yytext[0];
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%%
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