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libexpr: make "or"-as-variable less bogus

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The previous place where OR_KW was inserted into the grammar to allow
expressions like "map or [...]" led to a number of weird outcomes. By
moving it to expr_simple, expressions using "or" as a variable are now
parsed consistently with the rest of the language. Conflicts are
prevented by telling Bison that OR_KW has higher precedence than '.'.
This commit is contained in:
Ryan Hendrickson 2024-07-16 17:54:32 -04:00
parent 9300f855fc
commit 3b4892071d
2 changed files with 14 additions and 6 deletions
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10
src/libexpr/parser.y
View file

@ -158,6 +158,9 @@ static void setDocPosition(const LexerState & lexerState, ExprLambda * lambda, P
%nonassoc '?' %nonassoc '?'
%nonassoc NEGATE %nonassoc NEGATE
%precedence '.'
%precedence OR_KW
%% %%
start: expr { state->result = $1; }; start: expr { state->result = $1; };
@ -248,10 +251,6 @@ expr_select
{ $$ = new ExprSelect(CUR_POS, $1, std::move(*$3), nullptr); delete $3; } { $$ = new ExprSelect(CUR_POS, $1, std::move(*$3), nullptr); delete $3; }
| expr_simple '.' attrpath OR_KW expr_select | expr_simple '.' attrpath OR_KW expr_select
{ $$ = new ExprSelect(CUR_POS, $1, std::move(*$3), $5); delete $3; } { $$ = new ExprSelect(CUR_POS, $1, std::move(*$3), $5); delete $3; }
| /* Backwards compatibility: because Nixpkgs has a rarely used
function named ‘or’, allow stuff like ‘map or [...]’. */
expr_simple OR_KW
{ $$ = new ExprCall(CUR_POS, $1, {new ExprVar(CUR_POS, state->s.or_)}); }
| expr_simple | expr_simple
; ;
@ -263,6 +262,9 @@ expr_simple
else else
$$ = new ExprVar(CUR_POS, state->symbols.create($1)); $$ = new ExprVar(CUR_POS, state->symbols.create($1));
} }
| /* Backwards compatibility: because Nixpkgs has a rarely used
function named ‘or’, allow stuff like ‘map or [...]’. */
OR_KW { $$ = new ExprVar(CUR_POS, state->s.or_); }
| INT_LIT { $$ = new ExprInt($1); } | INT_LIT { $$ = new ExprInt($1); }
| FLOAT_LIT { $$ = new ExprFloat($1); } | FLOAT_LIT { $$ = new ExprFloat($1); }
| '"' string_parts '"' { $$ = $2; } | '"' string_parts '"' { $$ = $2; }

10
tests/unit/libexpr/trivial.cc
View file

@ -190,7 +190,13 @@ namespace nix {
ASSERT_THAT(*b->value, IsIntEq(1)); ASSERT_THAT(*b->value, IsIntEq(1));
} }
TEST_F(TrivialExpressionTest, orCantBeUsed) { TEST_F(TrivialExpressionTest, orCanBeUsed) {
ASSERT_THROW(eval("let or = 1; in or"), Error); auto v = eval("let or = 1; in or");
ASSERT_THAT(v, IsIntEq(1));
}
TEST_F(TrivialExpressionTest, orHasCorrectPrecedence) {
auto v = eval("let inherit (builtins) add; or = 2; in add 1 or");
ASSERT_THAT(v, IsIntEq(3));
} }
} /* namespace nix */ } /* namespace nix */