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Diffstat (limited to 'doc/language/keyword/cpsc-keyword-operator.7.md')
| -rw-r--r-- | doc/language/keyword/cpsc-keyword-operator.7.md | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/doc/language/keyword/cpsc-keyword-operator.7.md b/doc/language/keyword/cpsc-keyword-operator.7.md index e18a5e5..6c29370 100644 --- a/doc/language/keyword/cpsc-keyword-operator.7.md +++ b/doc/language/keyword/cpsc-keyword-operator.7.md @@ -31,7 +31,7 @@ Binary operators are `+ - * / DIV MOD & = <> < <= > >= AND OR`. Unary operators Operands match exact static types, without implicit conversions, following OVERLOAD rules. For example, an INTEGER operand does not match a REAL parameter. Visible global definitions and methods of the left operand's class participate together. The selected method must be accessible: PRIVATE never causes a public fallback. Included units provide operators using the ordinary INCLUDE visibility rules. -Return types also distinguish operator overloads. When the context requires a result type (assignment, RETURN, condition, CASE comparison, subscript and similar positions), only definitions returning exactly that type match; if the operands match but no result does, the error is `No matching overload for OPERATOR +(T, U) returning R`. A cast `(R) expr` only prefers R and otherwise selects by operands before converting. Without an expected result type, such as OUTPUT or an operand of another operator, a unique operand match is selected and definitions that differ only by return type are ambiguous. +Return types also distinguish operator overloads. When the context requires a result type (assignment, RETURN, condition, CASE comparison, subscript and similar positions), only definitions returning exactly that type match; if the operands match but no result does, the error is `No matching overload for OPERATOR +(T, U) returning R`. A cast `(R) expr` only prefers R and otherwise selects by operands before converting. Without an expected result type, such as OUTPUT or an operand of another operator, a unique operand match is selected; definitions that differ only by return type need a `RETURNS DEFAULT type` declaration to avoid ambiguity. DEFAULT follows the same rules as ordinary functions and does not resolve global/member operator ties; see [cpsc-keyword-default(7)](cpsc-keyword-default.7.md). The expression has the selected function's declared return type. Comparisons and logic may return any supported function result type: a comparison returning STRING can be printed or assigned to STRING, but a BOOLEAN context requires an overload returning BOOLEAN. CASE comparisons follow the same result-type rule and must return BOOLEAN. A VOID result may be discarded through an explicit call but cannot be used as a value. |