terminfo: nsterm and Terminal.app 2.5.3 (343.7) from OS X 10.10

[Leonardo Brondani Schenkel]

Hello,

I would like to report some missing key mappings and apparent key 
inconsistencies between the default, out-of-the-box behavior of 
Terminal.app 2.5.3 (343.7) shipped with OS X 10.10 and the definition of 
'nsterm' in the latest terminfo database (version 1.525, 2014-10-19 
01:16:56).

For reference, this is the output of 'infocmp' when $TERM=="nsterm":

nsterm|Apple_Terminal|AppKit Terminal.app,
        am, bce, hs, mir, msgr, npc, xenl, xon,
        colors#256, cols#80, it#8, lines#24, pairs#32767, wsl#50,
        acsc=``aaffggjjkkllmmnnooppqqrrssttuuvvwwxxyyzz{{||}}~~,
        bel=^G, blink=\E[5m, bold=\E[1m, civis=\E[?25l,
        clear=\E[H\E[J, cnorm=\E[?25h, cr=^M,
        csr=\E[%i%p1%d;%p2%dr, cub=\E[%p1%dD, cub1=^H,
        cud=\E[%p1%dB, cud1=^J, cuf=\E[%p1%dC, cuf1=\E[C,
        cup=\E[%i%p1%d;%p2%dH, cuu=\E[%p1%dA, cuu1=\E[A,
        dch=\E[%p1%dP, dch1=\E[P, dim=\E[2m, dl=\E[%p1%dM,
        dl1=\E[M, dsl=\E]2;\007, ed=\E[J, el=\E[K, el1=\E[1K,
        enacs=\E(B\E)0, flash=\E[?5h$<200/>\E[?5l, fsl=^G,
        home=\E[H, hpa=\E[%i%p1%dG, ht=^I, hts=\EH, ich=\E[%p1%d@,
        ich1=\E[@, il=\E[%p1%dL, il1=\E[L, ind=^J, invis=\E[8m,
        ka1=\EOq, ka3=\EOs, kb2=\EOr, kbs=\177, kc1=\EOp, kc3=\EOn,
        kcub1=\EOD, kcud1=\EOB, kcuf1=\EOC, kcuu1=\EOA,
        kdch1=\E[3~, kend=\E[F, kent=\EOM, kf1=\EOP, kf10=\E[21~,
        kf11=\E[23~, kf12=\E[24~, kf13=\E[25~, kf14=\E[26~,
        kf15=\E[28~, kf16=\E[29~, kf17=\E[31~, kf18=\E[22~,
        kf19=\E[33~, kf2=\EOQ, kf20=\E[34~, kf3=\EOR, kf4=\EOS,
        kf5=\E[15~, kf6=\E[17~, kf7=\E[18~, kf8=\E[19~, kf9=\E[20~,
        khome=\E[H, knp=\E[6~, kpp=\E[5~, op=\E[0m, rc=\E8,
        rev=\E[7m, ri=\EM, rmacs=^O, rmam=\E[?7l,
        rmcup=\E[2J\E[?47l\E8, rmir=\E[4l, rmkx=\E[?1l\E>,
        rmso=\E[m, rmul=\E[m,
        rs2=\E>\E[?3l\E[?4l\E[?5l\E[?7h\E[?8h, sc=\E7,
        setab=\E[%?%p1%{8}%<%t4%p1%d%e%p1%{16}%<%t10%p1%{8}%-%d%e48;5;%p1%d%;m,
        setaf=\E[%?%p1%{8}%<%t3%p1%d%e%p1%{16}%<%t9%p1%{8}%-%d%e38;5;%p1%d%;m,
        
sgr=\E[0%?%p6%t;1%;%?%p2%t;4%;%?%p1%p3%|%t;7%;%?%p4%t;5%;%?%p5%t;2%;%?%p7%t;8%;m%?%p9%t\016%e\017%;,
        sgr0=\E[m\017, smacs=^N, smam=\E[?7h, smcup=\E7\E[?47h,
        smir=\E[4h, smkx=\E[?1h\E=, smso=\E[7m, smul=\E[4m,
        tbc=\E[3g, tsl=\E]2;, u6=\E[%i%d;%dR, u7=\E[6n,
        u8=\E[?1;2c, u9=\E[c, vpa=\E[%i%p1%dd,

Out-of-the box Terminal.app is configured to generate the following 
sequences that are not described in terminfo:

kLFT=\E[1;2D
kLFT3=\Eb
kLFT5=\E[1;5D
kRIT=\E[1;2C
kRIT3=\Ef
kRIT5=\E[1;2C
kDC=\E[3;2~
kDC5=\E[3;5~
kDC7=\E\E[3;5~
kcbt=\E[Z

I suggest that these new capabilities are added to 'nsterm-bce'. The 
comments above that entry seem to mention the existence of these 
bindings but I am not sure why they were not included. (Unfortunately I 
don't have access to a pre-OS X 10.10 installation, so I can't really 
confirm if all those bindings were the same in old versions of 
Terminal.app.)

This is probably well-known, but the arrows and Home/End send different 
sequences:

        1       2
kuu1    \E[A    \E[OA
kud1    \E[B    \E[OB
kuf1    \E[C    \E[OC
kub1    \E[D    \E[OD
khome   \E[H    \E[OH
kend    \E[F    \E[OF

Terminal.app starts in "mode 1" and switches to "mode 2" when it 
receives a 'smkx' (defined as \E[?1h\E=) and stays in "mode 2" until it 
receives a 'rmkx' (defined as \E[?1l\E>) and reverts back to "mode 1".

However, compare this to the 'nsterm' entry in terminfo:

kcub1=\EOD, (mode 2)
kcud1=\EOB, (mode 2)
kcuf1=\EOC, (mode 2)
kcuu1=\EOA, (mode 2)
kend=\E[F,  (mode 1)
khome=\E[H, (mode 1)

You can see that the expected mode of the Home/End keys do not match the 
mode of the arrow keys, so either one of them will be wrong in any of 
the two modes. I suspect that the intent was for terminfo to have 
mappings for "mode 2" — if I'm correct, then 'nsterm-bce' should be 
changed so:

kend=\E[OF, khome=\E[OH

or even better:

use=xterm+app

Maybe these changes could even be made to 'nsterm-16color', but then 
again I can't really test old versions of Terminal.app.

It may be worth noticing that by default PageUp/PageDn/Home/End are not 
sent to the application but are used by Terminal.app to scroll its 
buffer and to send those keys it's necessary to simultaneously press the 
Shift key. However, if the terminal is in the alternate screen then the 
behavior is reversed: these keys are sent directly to the application 
and by pressing Shift you can scroll the buffer.

What is your opinion about these proposed changes? Are they reasonable?

Cheers,
// Leonardo.