diff options
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 33 |
1 files changed, 19 insertions, 14 deletions
@@ -4839,8 +4839,8 @@ determine the initial value of the place. Otherwise it is ignored. The vecref place denotes a vector element, allowing vector elements to be treated as assignment places. -The dwim/[] place denotes a vector element, list element, or hash table, -depending on the type of obj. +The dwim/[] place denotes a vector element, list element, string, or hash +table, depending on the type of obj. .SS Operator dwim @@ -4903,29 +4903,32 @@ See the section on Range Indexing below. Retrieve the specified element of a string. This is equivalent to (chr-str <string> <index>). +.IP [<string> <from-index>..<to-below-index>] +Retrieve the specified range of characters from the string, exactly as if +using (sub-str <string> <from-index> <to-below-index>). +The range of elements is specified in the car and cdr fields of a cons cell, +for which the .. (dotdot) syntactic sugar is useful. +See the section on Indexing below. + .IP [<hash-table> <key> <default-value>] Retrieve a value from the hash table corresponding to <key>, or <default-value> if there is no such entry. -The list, vector and hash table forms of dwim denote places -that can be assigned. - -The list and vector range forms can be assigned only using the set operator, -not using the others like push and inc. Assigning to a vector range modifies -the vector object; it is implemented using replace-vec. Assigning to a list -range updates the form which contains the list, so the expression denoting the -list must be an assignable place. +The places denoted by the dwim operator can be assigned. There are some +restrictions. List, string and vector ranges can only be replaced with set. The +other operators like push do not apply. Characters in a string can only be +assigned with set or incremented with inc and dec. .TP Range Indexing -Array and list range indexing is based from zero. The first element element -zero. Furthermore, the value -1 refers to the last element of the array or +Vector and list range indexing is based from zero. The first element element +zero. Furthermore, the value -1 refers to the last element of the vector or list, and -2 to the second last and so forth. So the range 1 .. -2 means "everything except for the first element and the last two". -The symbol t represents the position one past the end of the array or -list, so 0 .. t denotes the entire list or array, and the range t .. t +The symbol t represents the position one past the end of the vector, string or +list, so 0 .. t denotes the entire list or vector, and the range t .. t represents the empty range just beyond the last element. It is possible to assign to t .. t. For instance: @@ -6317,6 +6320,8 @@ Certain object types have a custom equal function. .SS Function sub-str +.SS Function replace-str + .SS Function cat-str .SS Function split-str |