快速、可移植、非图灵完备的渐进式表达式评估（Go）.zip

# Extensions CEL extensions are a related set of constants, functions, macros, or other features which may not be covered by the core CEL spec. ## Bindings Returns a cel.EnvOption to configure support for local variable bindings in expressions. ### Cel.Bind Binds a simple identifier to an initialization expression which may be used in a subsequenct result expression. Bindings may also be nested within each other. cel.bind(<varName>, <initExpr>, <resultExpr>) Examples: cel.bind(a, 'hello', cel.bind(b, 'world', a + b + b + a)) // "helloworldworldhello" // Avoid a list allocation within the exists comprehension. cel.bind(valid_values, [a, b, c], [d, e, f].exists(elem, elem in valid_values)) Local bindings are not guaranteed to be evaluated before use. ## Encoders Encoding utilies for marshalling data into standardized representations. ### Base64.Decode Decodes base64-encoded string to bytes. This function will return an error if the string input is not base64-encoded. base64.decode(<string>) -> <bytes> Examples: base64.decode('aGVsbG8=') // return b'hello' base64.decode('aGVsbG8') // error ### Base64.Encode Encodes bytes to a base64-encoded string. base64.encode(<bytes>) -> <string> Example: base64.encode(b'hello') // return 'aGVsbG8=' ## Math Math helper macros and functions. Note, all macros use the 'math' namespace; however, at the time of macro expansion the namespace looks just like any other identifier. If you are currently using a variable named 'math', the macro will likely work just as intended; however, there is some chance for collision. ### Math.Greatest Returns the greatest valued number present in the arguments to the macro. Greatest is a variable argument count macro which must take at least one argument. Simple numeric and list literals are supported as valid argument types; however, other literals will be flagged as errors during macro expansion. If the argument expression does not resolve to a numeric or list(numeric) type during type-checking, or during runtime then an error will be produced. If a list argument is empty, this too will produce an error. math.greatest(<arg>, ...) -> <double|int|uint> Examples: math.greatest(1) // 1 math.greatest(1u, 2u) // 2u math.greatest(-42.0, -21.5, -100.0) // -21.5 math.greatest([-42.0, -21.5, -100.0]) // -21.5 math.greatest(numbers) // numbers must be list(numeric) math.greatest() // parse error math.greatest('string') // parse error math.greatest(a, b) // check-time error if a or b is non-numeric math.greatest(dyn('string')) // runtime error ### Math.Least Returns the least valued number present in the arguments to the macro. Least is a variable argument count macro which must take at least one argument. Simple numeric and list literals are supported as valid argument types; however, other literals will be flagged as errors during macro expansion. If the argument expression does not resolve to a numeric or list(numeric) type during type-checking, or during runtime then an error will be produced. If a list argument is empty, this too will produce an error. math.least(<arg>, ...) -> <double|int|uint> Examples: math.least(1) // 1 math.least(1u, 2u) // 1u math.least(-42.0, -21.5, -100.0) // -100.0 math.least([-42.0, -21.5, -100.0]) // -100.0 math.least(numbers) // numbers must be list(numeric) math.least() // parse error math.least('string') // parse error math.least(a, b) // check-time error if a or b is non-numeric math.least(dyn('string')) // runtime error ### Math.BitOr Introduced at version: 1 Performs a bitwise-OR operation over two int or uint values. math.bitOr(<int>, <int>) -> <int> math.bitOr(<uint>, <uint>) -> <uint> Examples: math.bitOr(1u, 2u) // returns 3u math.bitOr(-2, -4) // returns -2 ### Math.BitAnd Introduced at version: 1 Performs a bitwise-AND operation over two int or uint values. math.bitAnd(<int>, <int>) -> <int> math.bitAnd(<uint>, <uint>) -> <uint> Examples: math.bitAnd(3u, 2u) // return 2u math.bitAnd(3, 5) // returns 3 math.bitAnd(-3, -5) // returns -7 ### Math.BitXor Introduced at version: 1 math.bitXor(<int>, <int>) -> <int> math.bitXor(<uint>, <uint>) -> <uint> Performs a bitwise-XOR operation over two int or uint values. Examples: math.bitXor(3u, 5u) // returns 6u math.bitXor(1, 3) // returns 2 ### Math.BitNot Introduced at version: 1 Function which accepts a single int or uint and performs a bitwise-NOT ones-complement of the given binary value. math.bitNot(<int>) -> <int> math.bitNot(<uint>) -> <uint> Examples math.bitNot(1) // returns -1 math.bitNot(-1) // return 0 math.bitNot(0u) // returns 18446744073709551615u ### Math.BitShiftLeft Introduced at version: 1 Perform a left shift of bits on the first parameter, by the amount of bits specified in the second parameter. The first parameter is either a uint or an int. The second parameter must be an int. When the second parameter is 64 or greater, 0 will be always be returned since the number of bits shifted is greater than or equal to the total bit length of the number being shifted. Negative valued bit shifts will result in a runtime error. math.bitShiftLeft(<int>, <int>) -> <int> math.bitShiftLeft(<uint>, <int>) -> <uint> Examples math.bitShiftLeft(1, 2) // returns 4 math.bitShiftLeft(-1, 2) // returns -4 math.bitShiftLeft(1u, 2) // return 4u math.bitShiftLeft(1u, 200) // returns 0u ### Math.BitShiftRight Introduced at version: 1 Perform a right shift of bits on the first parameter, by the amount of bits specified in the second parameter. The first parameter is either a uint or an int. The second parameter must be an int. When the second parameter is 64 or greater, 0 will always be returned since the number of bits shifted is greater than or equal to the total bit length of the number being shifted. Negative valued bit shifts will result in a runtime error. The sign bit extension will not be preserved for this operation: vacant bits on the left are filled with 0. math.bitShiftRight(<int>, <int>) -> <int> math.bitShiftRight(<uint>, <int>) -> <uint> Examples math.bitShiftRight(1024, 2) // returns 256 math.bitShiftRight(1024u, 2) // returns 256u math.bitShiftRight(1024u, 64) // returns 0u ### Math.Ceil Introduced at version: 1 Compute the ceiling of a double value. math.ceil(<double>) -> <double> Examples: math.ceil(1.2) // returns 2.0 math.ceil(-1.2) // returns -1.0 ### Math.Floor Introduced at version: 1 Compute the floor of a double value. math.floor(<double>) -> <double> Examples: math.floor(1.2) // returns 1.0 math.floor(-1.2) // returns -2.0 ### Math.Round Introduced at version: 1 Rounds the double value to the nearest whole number with ties rounding away from zero, e.g. 1.5 -> 2.0, -1.5 -> -2.0. math.round(<double>) -> <double> Examples: math.round(1.2) // returns 1.0 math.round(1.5) // returns 2.0 math.round(-1.5) // returns -2.0 ### Math.Trunc Introduced at version: 1 Truncates the fractional portion of the double value. math.trunc(<double>) -> <double> Examples: math.trunc(-1.3) // returns -1.0 math.trunc(1.3) // returns 1.0 ### Math.Abs Introduced at version: 1 Returns the absolute value of the numeric type provided as input. If the value is NaN, the output is NaN. If the input is int64 min, the function will result in an overflow error. math.abs(<double>) -> <double> math.abs(<int>) -> <int> math.abs(<uint>) -> <uint> Examples: math.abs(-1) // returns 1 math.abs(1) // returns 1 math.abs(-9223372036854775808) // overlflow error ### Math.Sign Introduced at version: 1 Returns the sign of the numeric type,