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diff --git a/src/cmd/ksh93/RELEASE88 b/src/cmd/ksh93/RELEASE88 new file mode 100644 index 0000000..2466e39 --- /dev/null +++ b/src/cmd/ksh93/RELEASE88 @@ -0,0 +1,422 @@ +This is a list of changes that have been made since the 11/16/88 version +of ksh. + +1. New features in 12/28/93 + a. Associative arrays. The new version of ksh supports both + associate arrays and the older indexed arrays with the same + array syntax. A new -A option of typeset is used to declare + an array to be associative. As with indexed arrays, $name is + equivalent to ${name[0]}. The prefix operator ! was added + to the parameter expansion syntax to expand to the list of + indices. For example, ${!name[@]} expands to the list of array + indices for variable name. + + b. Several additions have been made to shell arithmetic: + 1. The shell now performs floating point arithmetic. The + typeset options -F and -E have been added for floating + point and scientific notation respectively. + 2. The prefix and postfix ++ and -- operators. + 3. The comma and ?: operators. + 4. The math library functions. + 5. An arithmetic for statement of the form + for ((expr1; expr2; expr3)) + do ... + done + 6. Integer arithmetic extended up to base 64. + + c. Some additions to the macro expansion syntax have been made + to specify substrings and sub-arrays: + 1. ${name:expr} expands to the substring of ${name} starting at + the character position defined by arithmetic expression expr. + 2. ${name:expr1:expr2} expands to the substring of ${name} starting + at expr1 and consisting of at most expr2 characters. + 3. ${name[@]:expr} expands to the values of ${name[@]} starting at + the element defined by arithmetic expression expr. + 4. ${name[@]:expr1:expr2} expands to at most expr2 values of + ${name} starting at expr1. + 5. ${@:expr} expands the positional parameters starting at expr. + 6. ${@:expr1:expr2} expands to at most expr2 positional parameters + starting at expr1. + 7. ${!name} expands to the name of the variable named by name. + It will expand to name unless name is reference variable. + 8. ${!name[sub]} expands to the name of the subscript of the + given variable. If sub is @ or * the list of subscripts + is generated. + 9. ${!prefix*} and ${!prefix@} expand to the list of variable + names beginning with prefix. + 10. The substring operators, # and % can be now be applied + with aggregates (@ or *) and are applied to each. + 11. ${name/pattern/string} expands to the value of name with + the first occurrence of pattern replaced by string. + With aggregates (@ or *) this operation is applied to each. + 12. ${name/#pattern/string} Same as above but the pattern + to be replaced must match at the beginning. + 13. ${name/%pattern/string} Same as above but the pattern + to be replaced must match at the end. + 14. ${name//pattern/string} expands to the value of name with + the each occurrence of pattern replaced by string. + With aggregates (@ or *) this operation is applied to each. + + d. The name space for variables has been extended. The character '.' + can be used at the beginning of a name, and to separate identifiers + within a name. However, to create a name of the form, foo.bar, + the variable foo must exist. The namespace starting with .sh + is reserved for shell implementation variables. Exported + variable cannot contain a '.'. + + e. Compound assignments. The assignment syntax, varname=value, + has been extended to allow assignments of the form + varname=(assignment_list). As elsewhere in the shell + spaces or tabs are optional around the parentheses, and + no space is permitted between the varname and the =. The + assignment_list can be one of the following: + 1. A list of words. In this case each word is expanded as + in a for list and the resulting items become elements + of the indexed array varname. + 2. A list of subscript assignments in the form + [subscript]=value. In this, these elements become + elements of the associative array varname. + 3. A list of assignments; simple or compound. In this + case, each assignment is made to varname.name, where + name is the name of the enclosed assignment. + 4. Assignments in the form of readonly or typeset + statements. In this case each assignment is made as + in 3 above, and the attributes are given to the + corresponding variable. + In case 3 and 4 above, the value of "$varname" after + the above assignment is (assignment_list), where the + assignment_list produced would reproduce all of the + variables under varname.*. + + f. Function names of the form variable.action (called discipline + functions) can be defined where variable is any valid variable + name and action is get, set, or unset. The function variable.get + is invoked each time the variable is referenced. The set + discipline is invoked each time the variable is assigned to. + The unset discipline is invoked when a variable is unset. + The new variables .sh.name, .sh.subscript, and .sh.value are + defined inside the function body. Other shell extensions + may have their own set of discipline functions. + + g. The compound command !, which negates the return value of the + following pipeline, has been added. + + h. On systems that support dynamic loading with dlopen(), it is + now possible to add built-in commands at runtime with the + a builtin command named builtin. + + i. The following builtins have been added: + 1. command name [ ... ] + 2. sleep [decimal-seconds] + 3. builtin [-ds] [-f file] [name...] + 4. getconf name [pathname] + 5. disown [job...] + + j. An addition format for literal strings, $'....' can + be used where ever literal strings are valid. The string + inside the single quotes will be converted using the ANSI-C + escape conventions. Additionally, the escape sequence \E + expands to the escape character (default \033) whenever ANSI-C + escape sequences are recognized. + + k. A typeset -n option has been added which causes the value of a + variable to be treated as a reference to another variable so that + variables can be indirectly named. For example, if $1 contains + the name of a variable, then typeset -n foo=$1 causes the variable + foo to be synonymous with the variable whose name is $1. A builtin + alias, nameref='typeset -n' has been added to aid mnemonics. + Reference names cannot contain a '.'. Whenever that portion of + a variable up to the first '.' matches a reference name, the + reference value is substituted. For example, with nameref foo=.top, + then ${foo.bar} is equivalent to ${.top.bar}. When used as the + index of a for or select loop, each assignment causes a + new name reference to occur. + + l. The KEYBD trap has been added which is triggered when a key + or escape sequence is typed while reading from the keyboard + in an edit mode. This, combined with some new variables + makes it possible to program your key bindings in ksh. + + m. New variables have been added: + 1. FIGNORE defines a set of file names to be ignored in each + directory when performing pathname expansion, replacing + the rule that requires that a leading . be matched explicitly. + 2. Variable sh.edchar contains the value of the keyboard character + that has been entered when processing a KEYBD trap. If the value + is changed as part of the trap action, then the new value replaces + the key or keys that caused the trap. + 3. Variable sh.edcol is set to the character position of the cursor + within the input buffer during a KEYBD trap. + 4. Variable sh.edmode is set to the escape character when in vi + insert mode. + 5. Variable sh.edtext is set to the contents of the input buffer + during a KEYBD trap. + 6. HISTEDIT is checked before FCEDIT. FCEDIT is obsolete. + 7. HISTCMD is the number of the current command in the history + file. + 8. Variable .sh.version is set to the version string for + this shell. + 9. Variable .sh.name is set to the name of the variable + that that was referenced or assigned to when executing a get + or set discipline function. + 10. Variable .sh.subscript is set to the subscript for the variable + that was referenced or assign to when executing a get or + set discipline function. + 11. Variable .sh.value is set to the new value for the variable + that was assigned to when executing the set discipline function. + + n. New invocation and set -o options have been added: + 1. set -o notify (or set -b) causes background completion messages + to be displayed as soon as the job completes. + 2. There is a compile time option named KIA which enables + creation of a relational database for commands, variables + and functions defined and referenced by a script. The + option -I <filename>, causes the database to be generated + in <filename>. The database format can be queried via + the cql command. + o. ksh93 can read and evaluate pre-compiled scripts generated by + a separate program called shcomp. + p. More work on internationalization has been added: + 1. The decimal point character is processed per locale + 2. A $ can be placed in front of each string to indicate + that the string needs translation but is otherwise ignored. + This means that if a message catalog of all $"..." strings + is generated, then a program such as print $"hello world" + could display "bonjour monde" in the french locale. + q. Backreferences have been added to pattern matching. The sequence + \d, where d is a digit from 1-9, matches the same string as + the d-th previous parenthesis group. Backreferences + can be used within patterns, and within replacement strings + with any of the ${name/...} operators. + +2. Changes made in 12/28/93 + a. The output format of many commands has changed as follows: + 1. System error messages are displayed whenever a failure + is caused by a system call. + 2. The exit status has changed in many cases: + a. USAGE messages cause an exit status of 2. + b. Commands not found cause exit - 127. + c. Command found, but not executable - 126. + d. Terminated because of signal - 256+sig + 3. The output of values from built-ins that contain special + characters are quoted in a manner that then can be re-input. + 4. The trace output puts quotes around the output so that it + can be reused as input. + 5. The output for trap is in a format that can be reinput the + the shell to restore the traps. + 6. kill -l lists the signal names without numbers as + required by the POSIX standard. + + b. The following changes have been made to shell functions: + 1. The semantics of functions declared with name() has changed + to conform with the IEEE-POSIX 1003.2 standard. In particular, + these functions are executed in a dot script environment rather + than a separated function environment so that there are no + local variables and no scoping for traps. + 2. Functions declared as function name, preserve the old ksh + semantics can be also used as the first argument to the dot (.) + command to have them executed in a dot script environment. + + c. The command search rules have changed as follows: + 1. Special built-ins (those with a dagger in front of them) are + executed first. + 2. Functions are executed next. + 3. Other built-ins that do not require an executable version + (for example cd and read) come next. + 4. If the command name contains a slash, the pathname corresponding + to the command name is executed. + 5. If name corresponds to a previously encountered pathname + on the PATH variable, the corresponding command is executed. + 6. If the command name does not contain a slash, then the PATH + variable is used to find an executable by that name. If + the directory that the command is found is also contained in + the FPATH variable, then the command treated as a function. + If the shell has a built-in version of the command corresponding + to this command, then the built-in version of this command + is executed. Otherwise, the shell remembers that pathname + corresponding to this command name and executes this pathname. + 7. If the name is not found on PATH, then the directories in + FPATH are searched. If found, then the command is executed + as a function. + + d. Built-in commands options now conform to the IEEE-POSIX 1003.2 + conventions with some additions. In particular, + name -? + will now print a Usage line for name, except for true, false, + colon, login, newgrp, echo, [, and command. + + e. Tilde expansion is now performed as part of the word expansions. + The effect of this is that if word begins with ~ in ${name op word}, + it will be expanded unless escaped. + + f. Pathname expansion is no longer performed on redirection words + unless the shell is interactive. + + g. Changes to shell and options: + 1. The -n option has been enhanced to produce more warning and + portability messages. + 2. The -C option is equivalent to -o noclobber. Files are + created with O_EXCL when -C is on. + + h. The following changes have been made to [[...]]: + 1. A string by itself is equivalent to -n string. + 2. -e has been added as equivalent to -a. + 3. == has been added as equivalent =. + 4. -a and = are now considered obsolete. + 5. Arithmetic comparisons are now considered obsolete. + + i. kill has been changed as follows: + 1. Signal names can be upper case or lower case. + 2. Numerical arguments to kill -l cause the given signal names to + be displayed. + 3. String arguments to kill -l cause the given signal numbers to + be displayed. + 4. Synopsis changed for getopts conformance. + + j. print has a -f format option which is equivalent to + the IEEE POSIX printf. Both print -f format, and + printf have the following extensions from IEEE POSIX: + 1. Floating point formats are supported. + 2. Size and precision specifications can be *. + 3. The %d option can take an argument after precision to + specify the base that the number will be displayed. + 4. A %q format can be used to output a string quoted so + that it can be re-input to the shell. + 5. A %P format can be used to output the shell pattern which + corresponds to the give extended regular expression. + 6. For numerical fields, the arguments can be arithmetic + expressions which will be evaluated. + 7. The %n format works as described in ANSI-C. + + k. The following changes have been made to fc: + 1. It has been renamed hist. fc is now a predefined alias. + 2. hist uses ${HISTEDIT:-$FCEDIT}. FCEDIT is obsolete. + 3. A new -s option is equivalent to the obsolete -e -. + 4. If the first argument refers to a command earlier than the + first accessible command, it now implies the first accessible + command, so that hist -l 1 lists all accessible history commands. + + l. The dot command (.) has changed as follows: + 1. The argument can be the name of a function declared as + function name. The function will execute without creating a + new scope. + 2. If there are arguments to the given script or function, + the positional parameters are restored to their original + value when . completes. + + m. The read built-in has been changed as follows: + 1. A -A option to read has been added to allow the fields to be + read into an indexed array. + 2. A -t n option has been added which causes read to + timeout after n seconds when reading from a slow device. + 3. A -d char option has been added which causes the read + to terminate at char rather than at new-line. + + n. The trap command has been changed as follows: + 1. Trap names can be either upper case or lower case. + 2. Trap -p cause only the specified trap values to be displayed. + 3. The value of trap in a subshell will be the value in the parent + shell until a call to trap which changes the trap settings has + been made. Thus, savetraps=$(trap) works as required by the + POSIX standard. + + o. The exec command has been extended as follows: + 1. The -c option clears the environment first. + 2. The -a name option sets argv[0] to name for the program. + + p. true and false are built-ins, not aliases to built-ins. + + q. test has been modified to conform to the IEEE-POSIX 1003.2 + standard when there are three or less arguments. + + r. umask -S option displays the mask in a symbolic format. + + s. wait now returns the correct exit status of any previous + background job that has not been waited for, not just + the most recent one. + + t. The whence built-in has an option -a which causes all + uses for the given command name to be reported. + + u. unalias has -a option to clear all the aliases. + + v. The times built-in command has been removed. The time + reserved word, without a command, gives time cumulative + time for the shell and its children. A built-in alias + for times should enable scripts using times to continue + to run. + + w. Command substitution and arithmetic substitution will now be + performed for PS1, ENV, and PS4 evaluation in addition to + parameter expansion. + + x. The SECONDS variable now displays elapsed time in floating + point seconds with 3 places after the decimal point by + default. + + y. The getopts built-in now handles the complete libast optget + functionality. If any errors have occurred with getopts + when it has reached the end of arguments, then the Usage + message will be generated from the option string and the + exit status from getopts will be 2 rather than 1. The + usage message will be stored in the OPTARG variable if + the option string contains a leading colon; otherwise + it will be printed on standard error automatically. + + z. THE ENV file is only processed for interactive shell + invocations. In addition, the -x attributes for + aliases and functions is ignored. + + aa. The built-in edit modes have been changed as follows: + 1. The pathname completion and pathname listing options + now perform command completion and command listing + when applied to a word in the command position. + 2. In emacs mode ^N as the first related command after + the prompt will move to the next command relative to the + last known history position. + 3. In emacs mode, successive kill and delete commands will + accumulate their data in the kill buffer, by appending or + prepending as appropriate. This mode will be reset by any + command not adding something to the kill buffer. + 4. The control-T of emacs mode has been changed to behave like + control-T in gnu-emacs. + bb. The TMOUT variable also sets a limit for select timeouts + and default timeouts for read. + + +4. The source code has undergone significant modification. + a. Much of the code has been rewritten, In many cases this has + resulted in significant performance improvement. + + b. The code is organized differently. See the README files + for more details. + + c. Most configuration parameters now get generated using + the FEATURE mechanism of nmake. Other options are set + in the OPTIONS file. + + c. The are several new compile time options. See the README + file for details. Some of the old ones have been removed. + + d. The install script is a Mamfile that is generated by + nmake and processed by a script that comes with the + distribution. + + e. There are far fewer global names. This should make it + must easier to add built-in commands without worrying + about conflicts. + + f. The code uses the sfio library which makes it possible + to mix with stdio. + + g. The code is written in ANSI C with full prototypes. + The code is based on the IEEE POSIX 1003.1 standard. + The code can be compiled with K&R C and with C++ by + using the ANSI cpp that comes with nmake or running + the code through the proto filter before pre-processing. + This happens automatically with our shipping system. + + h. There is a programming interface for capturing references + and assignment to shell variables. It is also possible + to intercept variable creation and supply the array processing + function for that variable. See nval.3 for a description. |