Project P121
Attendance register
A mark for each student at each session - present, late, excused, absent or none - and attendance rates under four ways of counting, which flag different students: an absence, a missing mark and no sessions yet are three different nothings.
2 modules · 2 recorded sessionstext-menu UI in the terminalupdated 2026-10-17
Every screen below was recorded under CPython. When this page was built, the EML interpreter replayed each session from the same input and printed the same bytes.
About
A mark for each student at each session: present, late, excused or absent - or no mark at all, when the register was not taken or the student had not joined yet. Four ways of counting give four attendance rates, and they flag different students.
main.eml- the menu, the register, the rates and who is below 80%, taking a register, correcting a mark, and a new studentroll.eml- the register, the four rates, percentages to a tenth, the flags, the sessions not taken, and the changes
How each part works:
- A rate is present or late over one of four counts of sessions: 1. every session held; 2. the sessions since the student joined; 3. the sessions with a mark; 4. those, leaving out the excused ones. Percentages are rounded half up to a tenth, in whole numbers only.
- As in the corpus case
absent-vs-empty-vs-zero, an absence, a missing mark and a student with no sessions yet are three different things: - counting (1) or (2), a session nobody marked lowers everyone, and (1) counts Dana's sessions before joining as absences: 50.0% against 100.0%; - a new student with no marked session has no rate at all; (1) would give 0.0% and flag them. - The counts fall from (1) to (4) and the rates never drop, so each list of flagged students contains the next; the program names those flagged only when a session with no mark counts as an absence.
- As in the corpus case
attendance-register, the counts are a dict updated one mark at a time.
What is checked: menu choices 1 to 6; one mark per student, each P, L, E or A in either case, or skip; a student on the register, a session from the one they joined to the last, and a mark or none; a new name of up to 10 letters, not already there, and at most 8 students. An empty answer cancels.
Sessions: sessions/basic.in gives: - the register (session 3 not taken, Dana joining at session 4) and the rates: Ana and Dana flagged only when no mark counts as an absence; - Finn added, with no rate yet, and session 7 taken for all six; - Ana's session 3 corrected to P, and the rates; Cara's session 6 to no mark, and the register and the rates.
sessions/bad-input.in gives: - menu choices 0 and x; - registers: a cancel, two marks, an X, and PP; - corrections: a cancel, Zed, then Ana with a cancel, 0, 9 and x for the session, Dana's session 2 (before joining), and Ana's session 1 with a cancel, Q and PP; - new students: a cancel, Ana, Jo-Jo and Bartholomews, then Gia, Hal and Ivy, and Jon, one too many; - session 7 not taken, the register and the rates.
Built on the verified corpus cases attendance-register (a dict of counts kept across many small updates) and absent-vs-empty-vs-zero (three kinds of nothing, and a rule that treats them alike).
Recorded sessions
What the screen shows while someone uses the program. Each typed line appears after its prompt, the way a terminal shows it.
bad-input
interpreter: byte-equal== Attendance register ==
A mark for each student at each session: present, late, excused or absent - or no mark, when the register was not taken or the student had not joined.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 0
Pick a number from 1 to 6.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> x
Pick a number from 1 to 6.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 3
Session 7: a mark for each of Ana, Ben, Cara, Dana and Eli in turn (P, L, E or A), or skip if the register was not taken.
marks>
Cancelled.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 3
Session 7: a mark for each of Ana, Ben, Cara, Dana and Eli in turn (P, L, E or A), or skip if the register was not taken.
marks> P P
Type 5 marks, one for each student.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 3
Session 7: a mark for each of Ana, Ben, Cara, Dana and Eli in turn (P, L, E or A), or skip if the register was not taken.
marks> P X P P P
Each mark is P, L, E or A, separated by spaces.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 3
Session 7: a mark for each of Ana, Ben, Cara, Dana and Eli in turn (P, L, E or A), or skip if the register was not taken.
marks> PP P P P P
Each mark is P, L, E or A, separated by spaces.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student>
Cancelled.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Zed
No such student.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Ana
session (1 to 6)>
Cancelled.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Ana
session (1 to 6)> 0
Type a session from 1 to 6.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Ana
session (1 to 6)> 9
Type a session from 1 to 6.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Ana
session (1 to 6)> x
Type a session from 1 to 6.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Dana
session (1 to 6)> 2
Dana joined at session 4.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Ana
session (1 to 6)> 1
mark (P, L, E, A or none)>
Cancelled.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Ana
session (1 to 6)> 1
mark (P, L, E, A or none)> Q
Type P, L, E, A or none.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Ana
session (1 to 6)> 1
mark (P, L, E, A or none)> PP
Type P, L, E, A or none.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 5
name (up to 10 letters)>
Cancelled.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 5
name (up to 10 letters)> Ana
Ana is already on the register.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 5
name (up to 10 letters)> Jo-Jo
Type a name of up to 10 letters.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 5
name (up to 10 letters)> Bartholomews
Type a name of up to 10 letters.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 5
name (up to 10 letters)> Gia
Gia joins from session 7.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 5
name (up to 10 letters)> Hal
Hal joins from session 7.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 5
name (up to 10 letters)> Ivy
Ivy joins from session 7.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 5
name (up to 10 letters)> Jon
8 students is the most.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 3
Session 7: a mark for each of Ana, Ben, Cara, Dana, Eli, Gia, Hal and Ivy in turn (P, L, E or A), or skip if the register was not taken.
marks> skip
Session 7 recorded.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 1
Register (P present, L late, E excused, A absent, - no mark):
session 1 2 3 4 5 6 7
Ana P P - L P A -
Ben P A - P E P -
Cara P P - P P L -
Dana - - - P P P - joined at session 4
Eli A L - E E A -
Gia - - - - - - - joined at session 7
Hal - - - - - - - joined at session 7
Ivy - - - - - - - joined at session 7
Sessions 3 and 7: the register was not taken.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 2
Present or late, out of: (1) every session held, (2) the sessions since joining, (3) the sessions with a mark, (4) those without excused ones.
student (1) (2) (3) (4)
Ana 57.1% 57.1% 80.0% 80.0%
Ben 42.9% 42.9% 60.0% 75.0%
Cara 71.4% 71.4% 100.0% 100.0%
Dana 42.9% 75.0% 100.0% 100.0%
Eli 14.3% 14.3% 20.0% 33.3%
Gia 0.0% 0.0% - -
Hal 0.0% 0.0% - -
Ivy 0.0% 0.0% - -
Below 80%:
(1) Ana, Ben, Cara, Dana, Eli, Gia, Hal and Ivy
(2) Ana, Ben, Cara, Dana, Eli, Gia, Hal and Ivy
(3) Ben and Eli
(4) Ben and Eli
Flagged only when a session with no mark counts as an absence: Ana, Cara, Dana, Gia, Hal and Ivy.
No marked session yet, so no rate: Gia, Hal and Ivy. Counting every session held gives 0.0% instead.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 6
Bye.
What was typed (62 lines)
0
x
3
3
P P
3
P X P P P
3
PP P P P P
4
4
Zed
4
Ana
4
Ana
0
4
Ana
9
4
Ana
x
4
Dana
2
4
Ana
1
4
Ana
1
Q
4
Ana
1
PP
5
5
Ana
5
Jo-Jo
5
Bartholomews
5
Gia
5
Hal
5
Ivy
5
Jon
3
skip
1
2
6
basic
interpreter: byte-equal== Attendance register ==
A mark for each student at each session: present, late, excused or absent - or no mark, when the register was not taken or the student had not joined.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 1
Register (P present, L late, E excused, A absent, - no mark):
session 1 2 3 4 5 6
Ana P P - L P A
Ben P A - P E P
Cara P P - P P L
Dana - - - P P P joined at session 4
Eli A L - E E A
Session 3: the register was not taken.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 2
Present or late, out of: (1) every session held, (2) the sessions since joining, (3) the sessions with a mark, (4) those without excused ones.
student (1) (2) (3) (4)
Ana 66.7% 66.7% 80.0% 80.0%
Ben 50.0% 50.0% 60.0% 75.0%
Cara 83.3% 83.3% 100.0% 100.0%
Dana 50.0% 100.0% 100.0% 100.0%
Eli 16.7% 16.7% 20.0% 33.3%
Below 80%:
(1) Ana, Ben, Dana and Eli
(2) Ana, Ben and Eli
(3) Ben and Eli
(4) Ben and Eli
Flagged only when a session with no mark counts as an absence: Ana and Dana.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 5
name (up to 10 letters)> Finn
Finn joins from session 7.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 2
Present or late, out of: (1) every session held, (2) the sessions since joining, (3) the sessions with a mark, (4) those without excused ones.
student (1) (2) (3) (4)
Ana 66.7% 66.7% 80.0% 80.0%
Ben 50.0% 50.0% 60.0% 75.0%
Cara 83.3% 83.3% 100.0% 100.0%
Dana 50.0% 100.0% 100.0% 100.0%
Eli 16.7% 16.7% 20.0% 33.3%
Finn 0.0% - - -
Below 80%:
(1) Ana, Ben, Dana, Eli and Finn
(2) Ana, Ben and Eli
(3) Ben and Eli
(4) Ben and Eli
Flagged only when a session with no mark counts as an absence: Ana, Dana and Finn.
No marked session yet, so no rate: Finn. Counting every session held gives 0.0% instead.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 3
Session 7: a mark for each of Ana, Ben, Cara, Dana, Eli and Finn in turn (P, L, E or A), or skip if the register was not taken.
marks> P P A E L P
Session 7 recorded.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 1
Register (P present, L late, E excused, A absent, - no mark):
session 1 2 3 4 5 6 7
Ana P P - L P A P
Ben P A - P E P P
Cara P P - P P L A
Dana - - - P P P E joined at session 4
Eli A L - E E A L
Finn - - - - - - P joined at session 7
Session 3: the register was not taken.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 2
Present or late, out of: (1) every session held, (2) the sessions since joining, (3) the sessions with a mark, (4) those without excused ones.
student (1) (2) (3) (4)
Ana 71.4% 71.4% 83.3% 83.3%
Ben 57.1% 57.1% 66.7% 80.0%
Cara 71.4% 71.4% 83.3% 83.3%
Dana 42.9% 75.0% 75.0% 100.0%
Eli 28.6% 28.6% 33.3% 50.0%
Finn 14.3% 100.0% 100.0% 100.0%
Below 80%:
(1) Ana, Ben, Cara, Dana, Eli and Finn
(2) Ana, Ben, Cara, Dana and Eli
(3) Ben, Dana and Eli
(4) Eli
Flagged only when a session with no mark counts as an absence: Ana, Cara and Finn.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Ana
session (1 to 7)> 3
mark (P, L, E, A or none)> P
Ana, session 3: - -> P.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 2
Present or late, out of: (1) every session held, (2) the sessions since joining, (3) the sessions with a mark, (4) those without excused ones.
student (1) (2) (3) (4)
Ana 85.7% 85.7% 85.7% 85.7%
Ben 57.1% 57.1% 66.7% 80.0%
Cara 71.4% 71.4% 83.3% 83.3%
Dana 42.9% 75.0% 75.0% 100.0%
Eli 28.6% 28.6% 33.3% 50.0%
Finn 14.3% 100.0% 100.0% 100.0%
Below 80%:
(1) Ben, Cara, Dana, Eli and Finn
(2) Ben, Cara, Dana and Eli
(3) Ben, Dana and Eli
(4) Eli
Flagged only when a session with no mark counts as an absence: Cara and Finn.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 4
student> Cara
session (1 to 7)> 6
mark (P, L, E, A or none)> none
Cara, session 6: L -> -.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 1
Register (P present, L late, E excused, A absent, - no mark):
session 1 2 3 4 5 6 7
Ana P P P L P A P
Ben P A - P E P P
Cara P P - P P - A
Dana - - - P P P E joined at session 4
Eli A L - E E A L
Finn - - - - - - P joined at session 7
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 2
Present or late, out of: (1) every session held, (2) the sessions since joining, (3) the sessions with a mark, (4) those without excused ones.
student (1) (2) (3) (4)
Ana 85.7% 85.7% 85.7% 85.7%
Ben 57.1% 57.1% 66.7% 80.0%
Cara 57.1% 57.1% 80.0% 80.0%
Dana 42.9% 75.0% 75.0% 100.0%
Eli 28.6% 28.6% 33.3% 50.0%
Finn 14.3% 100.0% 100.0% 100.0%
Below 80%:
(1) Ben, Cara, Dana, Eli and Finn
(2) Ben, Cara, Dana and Eli
(3) Ben, Dana and Eli
(4) Eli
Flagged only when a session with no mark counts as an absence: Cara and Finn.
1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit
choice> 6
Bye.
What was typed (21 lines)
1
2
5
Finn
2
3
P P A E L P
1
2
4
Ana
3
P
2
4
Cara
6
none
1
2
6
Modules
The program as written, entry module first. Each module transpiles to its own Python file, which is what eml project run executes.
main.eml(entry)
eml# P121 attendance register: the register, attendance rates under four
# ways of counting, taking a register, correcting a mark, a new student.
import roll
def plain(s):
0 => i
len(s) => j
while i < j and s[i] == " ":
i + 1 => i
while j > i and s[j - 1] == " ":
j - 1 => j
return s[i:j]
def pad(s, n):
s => out
while len(out) < n:
out + " " => out
return out
def lpad(s, n):
s => out
while len(out) < n:
" " + out => out
return out
def names_text(ns):
"" => out
for i in [0:len(ns) - 1]:
if i > 0 and i == len(ns) - 1:
out + " and " => out
elif i > 0:
out + ", " => out
out + ns[i] => out
return out
def numbers_text(ns):
[] => out
for x in ns:
out + [str(x)] => out
return names_text(out)
def mark_of(c):
# a typed mark as P, L, E or A, or "" if it is none of them
if c == "P" or c == "p":
return "P"
if c == "L" or c == "l":
return "L"
if c == "E" or c == "e":
return "E"
if c == "A" or c == "a":
return "A"
return ""
def find(reg, name):
for i in [0:len(reg) - 1]:
if reg[i][0] == name:
return i
return 0 - 1
def show(reg):
roll.held(reg) => n
"Register (P present, L late, E excused, A absent, - no mark):" ^0
" session " => head
for k in [1:n]:
head + lpad(str(k), 3) => head
head ^0
for st in reg:
" " + pad(st[0], 10) => line
for m in st[2]:
line + " " + m => line
if st[1] > 1:
line + " joined at session " + str(st[1]) => line
line ^0
roll.not_taken(reg) => gone
if len(gone) == 1:
("Session " + str(gone[0]) + ": the register was not taken.") ^0
elif len(gone) > 1:
("Sessions " + numbers_text(gone) + ": the register was not taken.") ^0
def rates(reg, line):
roll.held(reg) => n
("Present or late, out of: (1) every session held, (2) the sessions since joining, (3) the sessions with a mark, (4) those without excused ones.") ^0
" " + pad("student", 10) => head
for k in [1:4]:
head + lpad("(" + str(k) + ")", 10) => head
head ^0
for st in reg:
" " + pad(st[0], 10) => out
for p in roll.policies():
roll.rate(st, p, n) => r
out + lpad(roll.percent_text(r[0], r[1]), 10) => out
out ^0
("Below " + str(line) + "%:") ^0
[] => lists
for k in [0:3]:
roll.flagged(reg, roll.policies()[k], line) => f
lists + [f] => lists
if len(f) == 0:
(" (" + str(k + 1) + ") nobody") ^0
else:
(" (" + str(k + 1) + ") " + names_text(f)) ^0
[] => only
for name in lists[0]:
False => in3
for x in lists[2]:
if x == name:
True => in3
if not in3:
only + [name] => only
if len(only) > 0:
("Flagged only when a session with no mark counts as an absence: " + names_text(only) + ".") ^0
[] => none
for st in reg:
if roll.rate(st, "marked", n)[1] == 0:
none + [st[0]] => none
if len(none) > 0:
("No marked session yet, so no rate: " + names_text(none) + ". Counting every session held gives 0.0% instead.") ^0
def take_register(reg):
[] => names
for st in reg:
names + [st[0]] => names
("Session " + str(roll.held(reg) + 1) + ": a mark for each of " + names_text(names) + " in turn (P, L, E or A), or skip if the register was not taken.") ^0
plain(input("marks> ")) => t
if t == "":
"Cancelled." ^0
return reg
[] => marks
if t == "skip":
for st in reg:
marks + ["-"] => marks
else:
"" => w
for c in t + " ":
if c == " ":
if w != "":
if len(w) != 1 or mark_of(w) == "":
"Each mark is P, L, E or A, separated by spaces." ^0
return reg
marks + [mark_of(w)] => marks
"" => w
else:
w + c => w
if len(marks) != len(reg):
("Type " + str(len(reg)) + " marks, one for each student.") ^0
return reg
roll.take(reg, marks) => out
("Session " + str(roll.held(out)) + " recorded.") ^0
return out
def correct_mark(reg):
plain(input("student> ")) => name
if name == "":
"Cancelled." ^0
return reg
find(reg, name) => i
if i < 0:
"No such student." ^0
return reg
plain(input("session (1 to " + str(roll.held(reg)) + ")> ")) => t
if t == "":
"Cancelled." ^0
return reg
0 => k
if len(t) > 0 and len(t) <= 2:
True => digits
for c in t:
if c < "0" or c > "9":
False => digits
if digits:
int(t) => k
if k < 1 or k > roll.held(reg):
("Type a session from 1 to " + str(roll.held(reg)) + ".") ^0
return reg
if k < reg[i][1]:
(name + " joined at session " + str(reg[i][1]) + ".") ^0
return reg
plain(input("mark (P, L, E, A or none)> ")) => m
if m == "":
"Cancelled." ^0
return reg
"-" => mark
if m != "none":
if len(m) != 1 or mark_of(m) == "":
"Type P, L, E, A or none." ^0
return reg
mark_of(m) => mark
reg[i][2][k - 1] => before
roll.correct(reg, i, k, mark) => out
(name + ", session " + str(k) + ": " + before + " -> " + mark + ".") ^0
return out
def add(reg):
plain(input("name (up to 10 letters)> ")) => name
if name == "":
"Cancelled." ^0
return reg
if len(name) > 10:
"Type a name of up to 10 letters." ^0
return reg
for c in name:
if not ((c >= "a" and c <= "z") or (c >= "A" and c <= "Z")):
"Type a name of up to 10 letters." ^0
return reg
if find(reg, name) >= 0:
(name + " is already on the register.") ^0
return reg
if len(reg) >= 8:
"8 students is the most." ^0
return reg
roll.add_student(reg, name) => out
(name + " joins from session " + str(roll.held(out) + 1) + ".") ^0
return out
roll.default_register() => reg
80 => line
"== Attendance register ==" ^0
"A mark for each student at each session: present, late, excused or absent - or no mark, when the register was not taken or the student had not joined." ^0
True => running
while running:
"" ^0
"1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit" ^0
plain(input("choice> ")) => choice
if choice == "1":
show(reg)
elif choice == "2":
rates(reg, line)
elif choice == "3":
take_register(reg) => reg
elif choice == "4":
correct_mark(reg) => reg
elif choice == "5":
add(reg) => reg
elif choice == "6":
False => running
else:
"Pick a number from 1 to 6." ^0
"Bye." ^0
Python projection (main.py)
import roll
def plain(s):
i = 0
j = len(s)
while i < j and s[i] == " ":
i = i + 1
while j > i and s[j - 1] == " ":
j = j - 1
return s[i:j]
def pad(s, n):
out = s
while len(out) < n:
out = out + " "
return out
def lpad(s, n):
out = s
while len(out) < n:
out = " " + out
return out
def names_text(ns):
out = ""
for i in range(0, len(ns)):
if i > 0 and i == len(ns) - 1:
out = out + " and "
elif i > 0:
out = out + ", "
out = out + ns[i]
return out
def numbers_text(ns):
out = []
for x in ns:
out = out + [str(x)]
return names_text(out)
def mark_of(c):
if c == "P" or c == "p":
return "P"
if c == "L" or c == "l":
return "L"
if c == "E" or c == "e":
return "E"
if c == "A" or c == "a":
return "A"
return ""
def find(reg, name):
for i in range(0, len(reg)):
if reg[i][0] == name:
return i
return 0 - 1
def show(reg):
n = roll.held(reg)
print("Register (P present, L late, E excused, A absent, - no mark):")
head = " session "
for k in range(1, n+1):
head = head + lpad(str(k), 3)
print(head)
for st in reg:
line = " " + pad(st[0], 10)
for m in st[2]:
line = line + " " + m
if st[1] > 1:
line = line + " joined at session " + str(st[1])
print(line)
gone = roll.not_taken(reg)
if len(gone) == 1:
print("Session " + str(gone[0]) + ": the register was not taken.")
elif len(gone) > 1:
print("Sessions " + numbers_text(gone) + ": the register was not taken.")
def rates(reg, line):
n = roll.held(reg)
print("Present or late, out of: (1) every session held, (2) the sessions since joining, (3) the sessions with a mark, (4) those without excused ones.")
head = " " + pad("student", 10)
for k in range(1, 5):
head = head + lpad("(" + str(k) + ")", 10)
print(head)
for st in reg:
out = " " + pad(st[0], 10)
for p in roll.policies():
r = roll.rate(st, p, n)
out = out + lpad(roll.percent_text(r[0], r[1]), 10)
print(out)
print("Below " + str(line) + "%:")
lists = []
for k in range(0, 4):
f = roll.flagged(reg, roll.policies()[k], line)
lists = lists + [f]
if len(f) == 0:
print(" (" + str(k + 1) + ") nobody")
else:
print(" (" + str(k + 1) + ") " + names_text(f))
only = []
for name in lists[0]:
in3 = False
for x in lists[2]:
if x == name:
in3 = True
if not in3:
only = only + [name]
if len(only) > 0:
print("Flagged only when a session with no mark counts as an absence: " + names_text(only) + ".")
none = []
for st in reg:
if roll.rate(st, "marked", n)[1] == 0:
none = none + [st[0]]
if len(none) > 0:
print("No marked session yet, so no rate: " + names_text(none) + ". Counting every session held gives 0.0% instead.")
def take_register(reg):
names = []
for st in reg:
names = names + [st[0]]
print("Session " + str(roll.held(reg) + 1) + ": a mark for each of " + names_text(names) + " in turn (P, L, E or A), or skip if the register was not taken.")
t = plain(input("marks> "))
if t == "":
print("Cancelled.")
return reg
marks = []
if t == "skip":
for st in reg:
marks = marks + ["-"]
else:
w = ""
for c in t + " ":
if c == " ":
if w != "":
if len(w) != 1 or mark_of(w) == "":
print("Each mark is P, L, E or A, separated by spaces.")
return reg
marks = marks + [mark_of(w)]
w = ""
else:
w = w + c
if len(marks) != len(reg):
print("Type " + str(len(reg)) + " marks, one for each student.")
return reg
out = roll.take(reg, marks)
print("Session " + str(roll.held(out)) + " recorded.")
return out
def correct_mark(reg):
name = plain(input("student> "))
if name == "":
print("Cancelled.")
return reg
i = find(reg, name)
if i < 0:
print("No such student.")
return reg
t = plain(input("session (1 to " + str(roll.held(reg)) + ")> "))
if t == "":
print("Cancelled.")
return reg
k = 0
if len(t) > 0 and len(t) <= 2:
digits = True
for c in t:
if c < "0" or c > "9":
digits = False
if digits:
k = int(t)
if k < 1 or k > roll.held(reg):
print("Type a session from 1 to " + str(roll.held(reg)) + ".")
return reg
if k < reg[i][1]:
print(name + " joined at session " + str(reg[i][1]) + ".")
return reg
m = plain(input("mark (P, L, E, A or none)> "))
if m == "":
print("Cancelled.")
return reg
mark = "-"
if m != "none":
if len(m) != 1 or mark_of(m) == "":
print("Type P, L, E, A or none.")
return reg
mark = mark_of(m)
before = reg[i][2][k - 1]
out = roll.correct(reg, i, k, mark)
print(name + ", session " + str(k) + ": " + before + " -> " + mark + ".")
return out
def add(reg):
name = plain(input("name (up to 10 letters)> "))
if name == "":
print("Cancelled.")
return reg
if len(name) > 10:
print("Type a name of up to 10 letters.")
return reg
for c in name:
if not (c >= "a" and c <= "z" or c >= "A" and c <= "Z"):
print("Type a name of up to 10 letters.")
return reg
if find(reg, name) >= 0:
print(name + " is already on the register.")
return reg
if len(reg) >= 8:
print("8 students is the most.")
return reg
out = roll.add_student(reg, name)
print(name + " joins from session " + str(roll.held(out) + 1) + ".")
return out
reg = roll.default_register()
line = 80
print("== Attendance register ==")
print("A mark for each student at each session: present, late, excused or absent - or no mark, when the register was not taken or the student had not joined.")
running = True
while running:
print("")
print("1) register 2) rates 3) take the register 4) correct a mark 5) add a student 6) quit")
choice = plain(input("choice> "))
if choice == "1":
show(reg)
elif choice == "2":
rates(reg, line)
elif choice == "3":
reg = take_register(reg)
elif choice == "4":
reg = correct_mark(reg)
elif choice == "5":
reg = add(reg)
elif choice == "6":
running = False
else:
print("Pick a number from 1 to 6.")
print("Bye.")
roll.eml
eml# P121 attendance register - students, sessions and a mark for each: P
# present, L late, E excused, A absent, or no mark at all (the register was
# not taken, or the student had not joined). As in the corpus case
# absent-vs-empty-vs-zero, an absence, a missing mark and a student with no
# sessions yet are three different nothings, and a rate that treats them
# alike flags the wrong students. As in attendance-register, the counts are
# a dict updated one mark at a time.
#
# A student is [name, session joined, marks]; marks holds one letter per
# session held, "-" for no mark.
def default_register():
return [["Ana", 1, ["P", "P", "-", "L", "P", "A"]], ["Ben", 1, ["P", "A", "-", "P", "E", "P"]], ["Cara", 1, ["P", "P", "-", "P", "P", "L"]], ["Dana", 4, ["-", "-", "-", "P", "P", "P"]], ["Eli", 1, ["A", "L", "-", "E", "E", "A"]]]
def held(reg):
if len(reg) == 0:
return 0
return len(reg[0][2])
def div(p, q):
# the whole part of p / q, for p >= 0 and q > 0
int(p / q) => f
while f * q > p:
f - 1 => f
while (f + 1) * q <= p:
f + 1 => f
return f
def counts(st):
# {letter: count} over a student's marks, "-" included
{"P": 0, "L": 0, "E": 0, "A": 0, "-": 0} => c
for m in st[2]:
c[m] + 1 => c[m]
return c
def policies():
return ["all held", "since joining", "marked", "marked, not excused"]
def rate(st, policy, n):
# [present or late, the sessions it is out of] under a policy
counts(st) => c
c["P"] + c["L"] => present
if policy == "all held":
return [present, n]
if policy == "since joining":
return [present, n - st[1] + 1]
if policy == "marked":
return [present, c["P"] + c["L"] + c["E"] + c["A"]]
return [present, c["P"] + c["L"] + c["A"]]
def tenths(p, q):
# p / q as a percentage in tenths, rounded half up
return div(2000 * p + q, 2 * q)
def percent_text(p, q):
if q <= 0:
return "-"
tenths(p, q) => t
return str(div(t, 10)) + "." + str(t - 10 * div(t, 10)) + "%"
def below(p, q, line):
# under the line (a whole percent): only when there are sessions to count
return q > 0 and 100 * p < line * q
def flagged(reg, policy, line):
held(reg) => n
[] => out
for st in reg:
rate(st, policy, n) => r
if below(r[0], r[1], line):
out + [st[0]] => out
return out
def not_taken(reg):
# the sessions where nobody has a mark
[] => out
for k in [0:held(reg) - 1]:
True => none
for st in reg:
if st[2][k] != "-":
False => none
if none:
out + [k + 1] => out
return out
def take(reg, marks):
# a new session: one mark per student, or "-" for each when not taken
[] => out
for i in [0:len(reg) - 1]:
reg[i] => st
out + [[st[0], st[1], st[2] + [marks[i]]]] => out
return out
def add_student(reg, name):
held(reg) + 1 => j
[] => marks
for k in [1:held(reg)]:
marks + ["-"] => marks
return reg + [[name, j, marks]]
def correct(reg, i, k, mark):
# the student i's mark for session k (1-based)
[] => out
for x in [0:len(reg) - 1]:
reg[x] => st
if x == i:
[] => marks
for y in [0:len(st[2]) - 1]:
if y == k - 1:
marks + [mark] => marks
else:
marks + [st[2][y]] => marks
out + [[st[0], st[1], marks]] => out
else:
out + [st] => out
return out
Python projection (roll.py)
def default_register():
return [["Ana", 1, ["P", "P", "-", "L", "P", "A"]], ["Ben", 1, ["P", "A", "-", "P", "E", "P"]], ["Cara", 1, ["P", "P", "-", "P", "P", "L"]], ["Dana", 4, ["-", "-", "-", "P", "P", "P"]], ["Eli", 1, ["A", "L", "-", "E", "E", "A"]]]
def held(reg):
if len(reg) == 0:
return 0
return len(reg[0][2])
def div(p, q):
f = int(p / q)
while f * q > p:
f = f - 1
while (f + 1) * q <= p:
f = f + 1
return f
def counts(st):
c = {"P": 0, "L": 0, "E": 0, "A": 0, "-": 0}
for m in st[2]:
c[m] = c[m] + 1
return c
def policies():
return ["all held", "since joining", "marked", "marked, not excused"]
def rate(st, policy, n):
c = counts(st)
present = c["P"] + c["L"]
if policy == "all held":
return [present, n]
if policy == "since joining":
return [present, n - st[1] + 1]
if policy == "marked":
return [present, c["P"] + c["L"] + c["E"] + c["A"]]
return [present, c["P"] + c["L"] + c["A"]]
def tenths(p, q):
return div(2000 * p + q, 2 * q)
def percent_text(p, q):
if q <= 0:
return "-"
t = tenths(p, q)
return str(div(t, 10)) + "." + str(t - 10 * div(t, 10)) + "%"
def below(p, q, line):
return q > 0 and 100 * p < line * q
def flagged(reg, policy, line):
n = held(reg)
out = []
for st in reg:
r = rate(st, policy, n)
if below(r[0], r[1], line):
out = out + [st[0]]
return out
def not_taken(reg):
out = []
for k in range(0, held(reg)):
none = True
for st in reg:
if st[2][k] != "-":
none = False
if none:
out = out + [k + 1]
return out
def take(reg, marks):
out = []
for i in range(0, len(reg)):
st = reg[i]
out = out + [[st[0], st[1], st[2] + [marks[i]]]]
return out
def add_student(reg, name):
j = held(reg) + 1
marks = []
for k in range(1, held(reg)+1):
marks = marks + ["-"]
return reg + [[name, j, marks]]
def correct(reg, i, k, mark):
out = []
for x in range(0, len(reg)):
st = reg[x]
if x == i:
marks = []
for y in range(0, len(st[2])):
if y == k - 1:
marks = marks + [mark]
else:
marks = marks + [st[2][y]]
out = out + [[st[0], st[1], marks]]
else:
out = out + [st]
return out