## Dokumentation zu: operators(LPC) ``` NAME operators DESCRIPTION These are the operators availailable in LPC. They are listed in the order of precedence (low priority first): expr1 , expr2 Evaluate 'expr1' and then 'expr2'. The returned value is the result of 'expr2'. The returned value of 'expr1' is thrown away. var = expr Evaluate 'expr', and assign the value to 'var'. The new value of 'var' is the result. var += expr Assign the value of 'expr' + 'var' to 'var'. This is mostly equivalent to "var = var + expr". var -= expr Similar to '+=' above. var &= expr var |= expr var ^= expr var <<= expr var >>= expr var >>>= expr var *= expr var %= expr var /= expr var &&= expr var ||= expr expr1 ? expr2 : expr3 Evaluates 'expr1' and branches according to its truth value. If it is true, the 'expr2' is evaluated and returned as result, else 'expr3'. expr1 || expr2 The result is true if 'expr1' or 'expr2' is true. 'expr2' is not evaluated if 'expr1' was true. expr1 && expr2 The result is true i 'expr1' and 'expr2' is true. 'expr2' is not evaluated if 'expr1' was false. expr1 | expr2 The result is the bitwise or of 'expr1' and 'expr2'. For arrays, the union set is computed: all elements from plus all those from which are not in . expr1 ^ expr2 The result is the bitwise xor of 'expr1' and 'expr2'. For arrays, the symmetric difference is computed: all elements from which are not in , plus all those from which are not in . expr1 & expr2 The result is the bitwise and of 'expr1' and 'expr2'. For arrays and strings, the intersection set (all elements resp. characters from expr1 which which are also in the expr2) is computed. Note: "aab" & "a" -> "aa" but ({ 'a','a','b' }) & ({ 'a' }) -> ({ 'a' }) Eventually the array behaviour will be changed to match the string behaviour. Intersecting an array with a mapping is equivalent to intersecting the array with the indices of the mapping: array & mapping = array & m_indices(mapping) Mappings can be intersected with another mapping or an array. The resulting mapping holds all those entries from the first mapping, which are also mentioned in the second mapping (as index) resp. in the array. expr1 == expr2 Compare values. Valid for strings, numbers, objects and closures. expr1 != expr1 Compare values. Valid for strings, numbers, objects and closures. expr1 > expr2 Valid for strings and numbers. expr1 >= expr2 Valid for strings and numbers. expr1 < expr2 Valid for strings and numbers. expr1 <= expr2 Valid for strings and numbers. expr1 << expr2 Shift 'expr1' left by 'expr2' bits; the sign bit is not preserved. expr1 >> expr2 Shift 'expr1' right by 'expr2' bits. This shift preserves the sign of 'expr1'. expr1 >>> expr2 Shift 'expr1' right by 'expr2' bits. This shift does not preserve the sign of 'expr1', instead it shifts in 0 bits. expr1 + expr2 Add 'expr1' and 'expr2'. If numbers, then arithmetic addition is used. If one of the expressions are a string, then that string is concatenated with the other value. If the expressions are arrays, the result is the right array appended to the left. If the expressions are mappings of equal width, the result is merger of the two mappings. If one key exists in both mappings, the element from the right mapping appears in the result. If the two mappings are of different width, the result is if non-empty, and otherwise. expr1 - expr2 Subtract 'expr2' from 'expr1'. Valid for numbers, strings, arrays, mappings. For arrays and strings, all occurrences of the elements resp. characters in 'expr2' are removed from 'expr1', and the result is returned. For mapping, all occurances of elemens in 'expr1' which have a matching key in 'expr2' are removed, and the result is returned. expr1 * expr2 Multiply 'expr1' with 'expr2'. If strings or arrays are multiplied with a number (zero or positive), the result is a repetition of the original string or array. expr1 % expr2 The modulo operator of numeric arguments. expr1 / expr2 Integer division. ++ var Increment the value of variable 'var', and return the new value. -- var Decrement the value of variable 'var', and return the new value. - var Compute the negative value of 'var'. ! var Compute the logical 'not' of an integer. ~ var The boolean 'not' of an integer. ( type ) var Return the value of converted to . can be 'string', 'int', 'object', 'float' or 'int*'. must be of a specific type for a conversion to take place; if is 'mixed' or unknown, the cast is purely declarative. Also, if the declared type of is that of , the value is not changed. NB. The literal number 0 is of unknown type, as it doubles as 'not initialized' for strings, objects, and arrays. The operator acts like the efuns to_string(), to_int(), to_object(), to_float() and to_array(). It is advisable to use the efuns directly instead of the cast. ({ type }) var is now assumed to have the type . This is purely declarative, the actual value of is not changed. var ++ Increment the value of variable 'var', and return the old value. var -- Decrement the value of variable 'var', and return the old value. expr1[expr2] The array or mapping given by 'expr1' is indexed by 'expr2'. expr1[expr2..expr3] Extracts a piece from an array or string. expr2 or expr3 may be omitted, default is the begin or end of expr1. Negative numbers for expr2 or expr3 mean ``count from before the beginning'', i.e. foo[-2..-1] is an empty array or string. foo[<2..<1] gives the 2nd and last element of the array resp. chars of the string. expr1->name(...) The symbolic form of call_other(). 'expr1' gives either an object or a string which is used as the file_name of an object, and calls the function 'name' in this object. expr1.name(...) The operator form of call_strict(). 'expr1' gives either an object or a string which is used as the file name of an object, and calls the function 'name' in this object. Throws an error, if the function does not exist. ident::name(...) Call the inherited function 'name' with the given parameters in the parent 'ident'. 'ident' may be given as string containing the full pathname, or as identifier containing the pure basename. If 'ident' is omitted, the last inherited function of this 'name' is called. ({ }) Array constructor. ([ ]) Mapping constructor. NOTE The closure operators are not described here. HISTORY LDMud 3.2.9 added '>>>', '>>>=', '&&=' and '||='. LDMud 3.2.10 extended '&' to mappings. LDMud 3.3 extended '|' and '^' to arrays. LDMud 3.6.2 added '.'. SEE ALSO arrays(LPC), alists(LPC), mappings(LPC), closures(LPC) ```

Start » Magierhandbuch » Docu » LPC » Operators Letzte Generierung: 25.04.2021, 01:58 mud@wl.mud.de 