diff options
Diffstat (limited to 'manuals/dc/E.1')
| -rw-r--r-- | manuals/dc/E.1 | 139 |
1 files changed, 113 insertions, 26 deletions
diff --git a/manuals/dc/E.1 b/manuals/dc/E.1 index a2468937..523dfc53 100644 --- a/manuals/dc/E.1 +++ b/manuals/dc/E.1 @@ -46,20 +46,12 @@ of computations. Arithmetic operations pop arguments off of the stack and push the results. .PP -If no files are given on the command-line as extra arguments (i.e., not -as \f[B]-f\f[R] or \f[B]--file\f[R] arguments), then dc(1) reads from -\f[B]stdin\f[R]. +If no files are given on the command-line, then dc(1) reads from +\f[B]stdin\f[R] (see the \f[B]STDIN\f[R] section). Otherwise, those files are processed, and dc(1) will then exit. .PP -This is different from the dc(1) on OpenBSD and possibly other dc(1) -implementations, where \f[B]-e\f[R] (\f[B]--expression\f[R]) and -\f[B]-f\f[R] (\f[B]--file\f[R]) arguments cause dc(1) to execute them -and exit. -The reason for this is that this dc(1) allows users to set arguments in -the environment variable \f[B]DC_ENV_ARGS\f[R] (see the \f[B]ENVIRONMENT -VARIABLES\f[R] section). -Any expressions given on the command-line should be used to set up a -standard environment. +If a user wants to set up a standard environment, they can use +\f[B]DC_ENV_ARGS\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). For example, if a user wants the \f[B]scale\f[R] always set to \f[B]10\f[R], they can set \f[B]DC_ENV_ARGS\f[R] to \f[B]-e 10k\f[R], and this dc(1) will always start with a \f[B]scale\f[R] of \f[B]10\f[R]. @@ -163,6 +155,19 @@ This is a \f[B]non-portable extension\f[R]. .RE .PP All long options are \f[B]non-portable extensions\f[R]. +.SH STDIN +.PP +If no files are given on the command-line and no files or expressions +are given by the \f[B]-f\f[R], \f[B]--file\f[R], \f[B]-e\f[R], or +\f[B]--expression\f[R] options, then dc(1) read from \f[B]stdin\f[R]. +.PP +However, there is a caveat to this. +.PP +First, \f[B]stdin\f[R] is evaluated a line at a time. +The only exception to this is if a string has been finished, but not +ended. +This means that, except for escaped brackets, all brackets must be +balanced before dc(1) parses and executes. .SH STDOUT .PP Any non-error output is written to \f[B]stdout\f[R]. @@ -859,8 +864,9 @@ of the register stack. .PP In non-extended register mode, a register name is just the single character that follows any command that needs a register name. -The only exception is a newline (\f[B]`\[rs]n'\f[R]); it is a parse -error for a newline to be used as a register name. +The only exceptions are: a newline (\f[B]`\[rs]n'\f[R]) and a left +bracket (\f[B]`['\f[R]); it is a parse error for a newline or a left +bracket to be used as a register name. .SS Extended Register Mode .PP Unlike most other dc(1) implentations, this dc(1) provides nearly @@ -1017,6 +1023,51 @@ greater than \f[B]1\f[R] and is less than \f[B]UINT16_MAX\f[R] (\f[B]2\[ha]16-1\f[R]), dc(1) will output lines to that length, including the backslash newline combo. The default line length is \f[B]70\f[R]. +.TP +\f[B]DC_SIGINT_RESET\f[R] +If this environment variable exists and contains an integer, then a +non-zero value makes dc(1) reset on \f[B]SIGINT\f[R], rather than exit, +and zero makes dc(1) exit. +.RS +.PP +If dc(1) is not in interactive mode (see the \f[B]INTERACTIVE MODE\f[R] +section), then this environment variable has no effect because dc(1) +exits on \f[B]SIGINT\f[R] when not in interactive mode. +.PP +This environment variable overrides the default, which can be queried +with the \f[B]-h\f[R] or \f[B]--help\f[R] options. +.RE +.TP +\f[B]DC_TTY_MODE\f[R] +If this environment variable exists and contains an integer, then a +non-zero value makes dc(1) use TTY mode (see the \f[B]TTY MODE\f[R] +section) when it is available, and zero makes dc(1) not use TTY mode. +.RS +.PP +If TTY mode is \f[I]not\f[R] available, then this environment variable +has no effect. +.PP +This environment variable overrides the default, which can be queried +with the \f[B]-h\f[R] or \f[B]--help\f[R] options. +.RE +.TP +\f[B]DC_PROMPT\f[R] +If this environment variable exists and contains an integer, then a +non-zero value makes dc(1) use a prompt when the TTY mode (see the +\f[B]TTY MODE\f[R] section) is available, and zero makes dc(1) not use a +prompt. +If this environment variable does not exist and \f[B]DC_TTY_MODE\f[R] +does, then the value of the \f[B]DC_TTY_MODE\f[R] environment variable +is used. +.RS +.PP +If TTY mode is \f[I]not\f[R] available, then this environment variable +has no effect. +.PP +This environment variable or the \f[B]DC_TTY_MODE\f[R] environment +variable override the default, which can be queried with the +\f[B]-h\f[R] or \f[B]--help\f[R] options. +.RE .SH EXIT STATUS .PP dc(1) returns the following exit statuses: @@ -1094,29 +1145,58 @@ and \f[B]--interactive\f[R] option can turn it on in other cases. In interactive mode, dc(1) attempts to recover from errors (see the \f[B]RESET\f[R] section), and in normal execution, flushes \f[B]stdout\f[R] as soon as execution is done for the current input. +dc(1) may also reset on \f[B]SIGINT\f[R] instead of exit, depending on +the contents or default for the \f[B]DC_SIGINT_RESET\f[R] environment +variable. .SH TTY MODE .PP If \f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are all -connected to a TTY, dc(1) turns on \[lq]TTY mode.\[rq] +connected to a TTY, dc(1) can turn on \[lq]TTY mode,\[rq] subject to +some settings. .PP -TTY mode is required for history to be enabled (see the \f[B]COMMAND -LINE HISTORY\f[R] section). -It is also required to enable special handling for \f[B]SIGINT\f[R] -signals. +If there is the environment variable \f[B]DC_TTY_MODE\f[R] in the +environment (see the \f[B]ENVIRONMENT VARIABLES\f[R] section), then if +that environment variable contains a non-zero integer, then dc(1) will +turn on TTY mode when \f[B]stdin\f[R], \f[B]stdout\f[R], and +\f[B]stderr\f[R] are all connected to a TTY. .PP -The prompt is enabled in TTY mode. +If the environment variable \f[B]DC_TTY_MODE\f[R] does \f[I]not\f[R] +exist, the default setting is used. +The default setting can be queried with the \f[B]-h\f[R] or +\f[B]--help\f[R] options. .PP TTY mode is different from interactive mode because interactive mode is required in the bc(1) specification (https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html), and interactive mode requires only \f[B]stdin\f[R] and \f[B]stdout\f[R] to be connected to a terminal. +.SS Command-Line History +.PP +Command-line history can only be enabled if TTY mode can be, i.e., that +\f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are connected to +a TTY. +See the \f[B]COMMAND LINE HISTORY\f[R] section for more information. +.SS Prompt +.PP +If dc(1) can be in TTY mode, a prompt can be enabled. +Like TTY mode itself, it can be turned on or off with an environment +variable: \f[B]DC_PROMPT\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] +section). +.PP +If the environment variable \f[B]DC_PROMPT\f[R] is a non-zero integer, +then command-line history is turned on when \f[B]stdin\f[R], +\f[B]stdout\f[R], and \f[B]stderr\f[R] are connected to a TTY and the +\f[B]-P\f[R] and \f[B]--no-prompt\f[R] options were not used. +The read prompt will be turned on under the same conditions, except that +the \f[B]-R\f[R] and \f[B]--no-read-prompt\f[R] options must also not be +used. .SH SIGNAL HANDLING .PP Sending a \f[B]SIGINT\f[R] will cause dc(1) to stop execution of the current input. -If dc(1) is in TTY mode (see the \f[B]TTY MODE\f[R] section), it will -reset (see the \f[B]RESET\f[R] section). +If dc(1) is in TTY mode (see the \f[B]TTY MODE\f[R] section) and/or the +\f[B]DC_SIGINT_RESET\f[R] environment variable, or its default, is +non-zero, dc(1) will reset (see the \f[B]RESET\f[R] section). Otherwise, it will clean up and exit. .PP Note that \[lq]current input\[rq] can mean one of two things. @@ -1142,15 +1222,22 @@ TTY mode, a \f[B]SIGHUP\f[R] will cause dc(1) to clean up and exit. .SH COMMAND LINE HISTORY .PP dc(1) supports interactive command-line editing. -If dc(1) is in TTY mode (see the \f[B]TTY MODE\f[R] section), history is -enabled. -Previous lines can be recalled and edited with the arrow keys. +.PP +If dc(1) can be in TTY mode (see the \f[B]TTY MODE\f[R] section), +history can be enabled. +This means that command-line history can only be enabled when +\f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are all +connected to a TTY. +.PP +Like TTY mode itself, it can be turned on or off with the environment +variable: \f[B]DC_TTY_MODE\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] +section). .PP \f[B]Note\f[R]: tabs are converted to 8 spaces. .SH LOCALES .PP This dc(1) ships with support for adding error messages for different -locales and thus, supports \f[B]LC_MESSAGS\f[R]. +locales and thus, supports \f[B]LC_MESSAGES\f[R]. .SH SEE ALSO .PP bc(1) |