术语信息参数化字符串中的延迟

Question

在terminfo的手册页中，提到$<>在编码中指定ms延迟，并且在其尖括号内是一个精度最多一个小数位的数字。

通过以下 python 脚本，我确认$<仅用于指定延迟，即没有参数化字符串，其中$<用于不指定延迟。

#!/usr/bin/env python3
# './test/data/stressTestTerms.txt' contains contains terminal names
# and directory './test/data/mirror' contains terminal databases of 2718 terminals
import subprocess
import re

def check_dollar_angular(caps):
string_caps = [cap for cap in caps.split(',') if '=' in cap]
# search for $<..> type delays in string caps
delay = r"$<(d+(.(d)+)?*?/?|(.(d)+)?*?/?)>"
caps_with_dollar = 0
delay_matches = 0
for cap in string_caps:
matches = list(re.finditer(delay, cap))
dollar_idx = cap.find('$<')
if dollar_idx != -1:
caps_with_dollar += 1
if any([True if match.start() == dollar_idx else False for match in matches]):
delay_matches += 1
if caps_with_dollar == delay_matches:
return True
else:
return False

if __name__ == "__main__":
with open('./test/data/stressTestTerms.txt') as terminal_names:
res = []
for each_terminal in terminal_names:
output = subprocess.run(
['infocmp', '-0', '-A', './test/data/mirror', each_terminal.strip()], stdout=subprocess.PIPE)
try:
output.check_returncode()
caps = output.stdout.decode('utf-8')
res.append(check_dollar_angular(caps))
except subprocess.CalledProcessError as e:
print(e)
if (not all(res)):
print(
"We have a terminal where in one of it's caps there is a dollar-angular but it doesn't signify delay")
else:
print(
"Success! no terminal found where '$<' is used for anything else other than specifying delay")

所以我的问题是，$<是否是文本/序列的一部分而不是代表延迟？例如。是否可以有这样的情况(现在或将来的终端)：$<%p1%d或$<A，其中没有结束尖括号，并且延迟并不意味着使用$<指定并且仍然是有效的 terminfo 序列？

Answer 1

手册页对语法非常明确：

A  delay  in  milliseconds  may appear anywhere in a string capability,
enclosed in $<..> brackets, as in el=EK$<5>,  and  padding  characters
are supplied by tputs(3x) to provide this delay.
o   The delay must be a number with at most one decimal place of preci-
sion; it may be followed by suffixes "*" or "/" or both.
o   A "*" indicates that the padding required is  proportional  to  the
number  of lines affected by the operation, and the amount given is
the per-affected-unit padding required.  (In  the  case  of  insert
character, the factor is still the number of lines affected.)
Normally, padding is advisory if the device has the xon capability;
it is used for cost computation but does not trigger delays.
o   A "/" suffix indicates that the padding is mandatory and  forces  a
delay of the given number of milliseconds even on devices for which
xon is present to indicate flow control.

如果没有结尾<，并且随附的文本不是有效的数字(可能带有*和/或/)，则tputs不应将其视为延迟。

在 ncurses 的终端数据库中，没有$<后不跟数字或"."的例子，但这并不意味着它是无效的，因为终端数据库应该能够描述大多数字符串(除了特殊情况，200(八进制)与相同，以适应 C 语言的 NUL 终止字符串。