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* String/path concatenation operator (`+').

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This commit is contained in:
Eelco Dolstra 2004-10-26 17:01:35 +00:00
parent ee401afad8
commit 9fa07b376d
6 changed files with 43 additions and 5 deletions
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14
src/libexpr/eval.cc
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@ -338,6 +338,20 @@ Expr evalExpr2(EvalState & state, Expr e)
return makeBool(attrs.get(name) != 0);
}
/* String or path concatenation. */
if (atMatch(m, e) >> "OpPlus" >> e1 >> e2) {
e1 = evalExpr(state, e1);
e2 = evalExpr(state, e2);
string s1, s2;
if (atMatch(m, e1) >> "Str" >> s1 &&
atMatch(m, e2) >> "Str" >> s2)
return makeString(s1 + s2);
else if (atMatch(m, e1) >> "Path" >> s1 &&
atMatch(m, e2) >> "Path" >> s2)
return makeString(canonPath(s1 + "/" + s2));
else throw Error("wrong argument types in `+' operator");
}
/* Barf. */
throw badTerm("invalid expression", e);
}