Enter RPN: R47: Glossary

Motivation

There are several terms used in the R47 which pop up often enough that even a new user might come across any of them. Few of these are R47-specific, having originated in the C43, WP43, or WP34s projects that preceded it.

Terms

AIM: Alpha Input Mode
ADM: Angle Display Mode; any of DEG, RAD, GRAD, D.MS, or MULπ, the current mode affects trig behavior, first DRG press interpretation, etc.
closed: an entered or calculated number not subject to being edited; details
EIM: Equation Input Mode
FDM: Fraction Display Mode
MIM: Matrix Input Mode; details
NIM: Numeric Input Mode; contrast “closed;” details
PEM: Program Entry Mode
TAM: Temporary Alpha Mode; details

Operating Mode State-Transition Diagram

Several of the terms above relate to R47 modes, which leaves us asking, “How does one move between those modes?”

OC: circle invisible diameter 2.5
IC: circle invisible diameter 1 with .c at OC.c

N:   oval "normal" bold fit at OC.c
PEM: oval "PEM"    fit at OC.n
AIM: oval "AIM"    fit at OC.s
EIM: oval "EIM"    fit at OC.w
TAM: oval "TAM"    fit at OC.e
NIM: oval "NIM"    fit at OC.se
MIM: oval "MIM"    fit at OC.sw
SW:  oval "timer"  fit at OC.nw
ASN: oval "assign" fit at OC.ne

arrow from N.n to PEM.s "🟧 PRGM" small aligned above ljust
spline → from PEM.s to IC.ne to N.c chop
line invis from PEM.s to IC.ne "EXIT or" small aligned above "🟧 PRGM" small aligned above

arrow ↔ from N.e to TAM.w "XEQ in" small "alpha field" small
"(one-shot)" small with .n at previous.s - (0, 0.075)

arrow from N.s to AIM.n "🟧 α" small aligned above
spline → from AIM.n to IC.sw to N.c chop
line invis from AIM.n to IC.sw "ENTER or" small aligned above "EXIT" small aligned below

arrow ← from EIM.e to N.w "🟧 EQN NEW" small aligned below
spline → from EIM.e to IC.nw to N.c chop
line invis from EIM.e to IC.nw "ENTER or" small aligned above "EXIT" small aligned below

arrow from N.se to NIM chop \
  "0-9, ., EEX, plus" small aligned below \
  "A-F in #BASE mode" small aligned below
arc ← from AIM.e to NIM.s chop "🟧 α" small aligned below

arrow ← from MIM to N.sw chop "🟧 MATX EDIT" small aligned above

arrow ← from SW.se to N.n chop "🟦 CLK STOPW" small aligned above

arrow from N.ne to ASN.sw chop "🟦 ASN" small aligned below

Normal mode

This is the mode in which no other modes are active. It is a presence defined by absence. 🤓

It is not merely the state of X being closed; that is true of several other modes.

All other R47 operating modes may be accessed from normal mode.

NIM: Numeric Input Mode

The many exits from NIM are not shown because nearly every key on the calculator will accomplish that. Broadly, one exits NIM either by calling any function operating on X or by pressing EXIT, ENTER, or R/S, resulting in a closed X value.

That leaves a short list of exceptions:

keys that instigate NIM will continue the input
CHS cannot enter NIM itself, but it will modify the input in progress
the arrow keys move through any active menu without terminating NIM
the shifts need a subsequent keypress to determine their action

MIM: Matrix Input Mode

The diagrammed transition to MIM presumes you already have a matrix in X. If not, it must be created somehow, as by putting the dimensions on the stack in X and Y, then pressing 🟧 MATX NEW.

Editing a cell puts the R47 temporarily into NIM, but terminating that input returns the calculator to MIM, not normal mode.

TAM: Temporary Alpha Mode

In contexts where alpha input is allowed, pressing XEQ — that is, 🟧 𝒂 without the shift needed to enter AIM — puts the calculator into alpha mode for that single input. It is especially useful for applying brief local labels and naming variables in programs. Reserve the full power of alpha mode for cases where you need more than the basics, or where you need to continue on in that mode for more than one entry.

Timer/Stopwatch Mode

The R47 code refers to a “timer” mode, which confusingly is entered via the STOPW function.

It is considered a mode because having the associated menu up causes the current timer to takes over the T register’s accustomed spot on the screen. As with any menu, EXIT leaves timer mode.

(See the companion article The Nerdiest Stopwatch for more details.)

Other Operating Modes

There are several more R47 modes not diagrammed above:

The register, flag, font, stat data, and assignment browsers
Awaiting confirmation or cancellation
The graphing and plotting modes

I see no reason to further complicate that diagram by showing all the transitions into and out of these modes.

(You may now wish to return to my R47 article index.)

R47: Glossary