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The precedence of the conditional operator in Perl is the same as in C, not as in C++. This is conveniently of higher precedence than a comma operator but lower than the precedence of most operators used in expressions within the ternary operator, so the use of parentheses is rarely required. [13]
In computer science, an operator-precedence parser is a bottom-up parser that interprets an operator-precedence grammar.For example, most calculators use operator-precedence parsers to convert from the human-readable infix notation relying on order of operations to a format that is optimized for evaluation such as Reverse Polish notation (RPN).
Perl 5 hashes are flat: keys are strings and values are scalars. However, values may be references to arrays or other hashes, and the standard Perl 5 module Tie::RefHash enables hashes to be used with reference keys. A hash variable is marked by a % sigil, to distinguish it from scalar, array, and other data types.
The rank of an operation is called its precedence, and an operation with a higher precedence is performed before operations with lower precedence. Calculators generally perform operations with the same precedence from left to right, [ 1 ] but some programming languages and calculators adopt different conventions.
In a language that supports operator overloading, and with the usual assumption that the '*' operator has higher precedence than the '+' operator, this is a concise way of writing: Add(a, Multiply(b, c)) However, the former syntax reflects common mathematical usage.
However, parser generators for context-free grammars often support the ability for user-written code to introduce limited amounts of context-sensitivity. (For example, upon encountering a variable declaration, user-written code could save the name and type of the variable into an external data structure, so that these could be checked against ...
In APL the precedence hierarchy for functions or operators is strictly positional: expressions are evaluated right-to-left. APL does not follow the usual operator precedence of other programming languages; for example, × does not bind its operands any more "tightly" than +. Instead of operator precedence, APL defines a notion of scope.
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