{ "id": "P056", "slug": "mini-spreadsheet", "key": "P056-mini-spreadsheet", "title": "Mini spreadsheet", "summary": "Cells A1 to F9 holding numbers, labels and formulas - + - * / with parentheses, cell references, SUM, MIN, MAX and AVG over ranges - kept as exact fractions. Every change recalculates the sheet in dependency order (Kahn's algorithm), and formulas caught in a cycle are found and marked instead of looping.", "entry": "main.eml", "ui": "terminal", "readme": "# P056 - Mini spreadsheet\n\nA small spreadsheet: columns A to F, rows 1 to 9. A cell holds a number, a\nlabel, or a formula that starts with =. Formulas use + - * / and\nparentheses, cells like B3, and SUM, MIN, MAX and AVG over cells and\nranges like D2:D4. Every change works the whole sheet out again, in an\norder where each formula comes after the formulas it reads. A formula\ncaught in a cycle is found and marked instead of looping forever.\n\n- `main.eml` - the menu, reading cells and contents, the value and formula\n views, and the sample\n- `sheet.eml` - formulas: the tokens, a parser that also works the value\n out, and the recalculation order\n- `frac.eml` - exact fractions, from P007 by way of P038 and P044\n\nHow each part works:\n\n- Values are exact fractions, so 1.2 * 10 is exactly 12 and a third is a\n third. The value view shows two decimal places and marks a rounded value\n with ~.\n- A formula is read by recursive descent: an expression is terms joined by\n + and -, a term is factors joined by * and /, and a factor is a number,\n a cell, a function, a minus sign before a factor, or an expression in\n parentheses. That is why =2+3*4 is 14. A formula that does not parse is\n refused with the reason, and nothing changes.\n- An empty cell counts as 0 in arithmetic. Arithmetic on a label gives\n #TEXT, and dividing by zero gives #DIV/0; an error passes on to every\n formula that reads it. SUM, MIN, MAX and AVG skip empty cells and\n labels. AVG of nothing is #DIV/0, and MIN or MAX of nothing is 0.\n- The order is Kahn's algorithm, as in the corpus case `topological-sort`.\n A formula is ready when every formula it reads is done; doing it may\n make others ready. Formulas never made ready are in a cycle, or read\n something that is, and they show #CYCLE until the cycle is broken. The\n order view lists both.\n\nWhat is checked: menu choices 1 to 7; cells from A1 to F9 (either case);\ncontents up to 60 characters; formulas that parse - numbers, cells A1 to\nF9, + - * / ( ), and SUM, MIN, MAX, AVG with cells and ranges separated by\ncommas. An empty answer cancels.\n\nSessions: `sessions/basic.in` loads a small order: three items, their\ntotals, a subtotal, tax at 8%, the total and the average.\n- The views show values, formulas and the order they were worked out:\n D2, D3, D4, D6, D9, D7, D8.\n- B3 changes to 1.25, and seven formulas are worked out again.\n- B7 becomes =D8/100. D7 reads B7 and D8 reads D7, so the three make a\n cycle; the rest still work.\n- B7 becomes 0.1, which breaks the cycle: tax 3.7 and total 40.7.\n\n`sessions/bad-input.in` gives:\n- menu choices 0 and x;\n- cells G1 and A0, and an empty cell;\n- empty contents;\n- the broken formulas =1+ and =SUM(B1;\n- =A1+1 in A1, a cycle of one;\n- =B1/C1 on empty cells;\n- a label, and a formula that multiplies it;\n- a SUM over the label, that formula and an empty cell;\n- 61 characters;\n- AVG of an empty column;\n- A1 emptied, then the values, the formulas and the order.\n\nBuilt on the verified corpus case `topological-sort` (Kahn's algorithm,\nwhich finds the cycle in what it leaves over).\n", "modules": [ { "name": "main.eml", "eml": "# P056 mini spreadsheet: six columns and nine rows of numbers, labels and\n# formulas. Formulas use + - * / ( ), cells like B3 and SUM, MIN, MAX, AVG\n# over ranges like A1:A5; every change recalculates the sheet in an order\n# where each formula comes after the formulas it reads, and a cycle is\n# found and named instead of looping forever.\nimport frac\nimport sheet\n\ndef trim(s):\n 0 => i\n len(s) => j\n while i < j and s[i] == \" \":\n i + 1 => i\n while j > i and s[j - 1] == \" \":\n j - 1 => j\n return s[i:j]\n\ndef shown(v):\n # A value in at most 10 characters: numbers to two decimal places with\n # ~ in front when rounded, labels cut to fit, errors as they are.\n if v[0] == \"e\":\n return v[1]\n if v[0] == \"t\":\n if len(v[1]) > 10:\n return v[1][0:9] + \"~\"\n return v[1]\n frac.decimal(v[1], 2) => s\n if len(s) > 6 and s[0:6] == \"about \":\n \"~\" + s[6:len(s)] => s\n if len(s) > 10:\n return \"#WIDE\"\n return s\n\ndef grid(cells, vals, formulas):\n \" \" => head\n for c in [0:5]:\n \" \" + \"ABCDEF\"[c] => h\n head + h[len(h) - 10:len(h)] + \" \" => head\n trim_right(head) ^0\n for r in [0:8]:\n \" \" + str(r + 1) + \" \" => line\n for c in [0:5]:\n r * 6 + c => k\n if formulas:\n cells[k] => s\n if len(s) > 10:\n s[0:9] + \"~\" => s\n else:\n shown(vals[k]) => s\n if formulas or vals[k][0] == \"t\":\n while len(s) < 10:\n s + \" \" => s\n else:\n while len(s) < 10:\n \" \" + s => s\n line + s + \" \" => line\n trim_right(line) ^0\n\ndef trim_right(s):\n len(s) => j\n while j > 0 and s[j - 1] == \" \":\n j - 1 => j\n return s[0:j]\n\ndef ask_cell(prompt):\n while True:\n trim(input(prompt)) => answer\n if answer == \"\":\n return -1\n sheet.cell_index(answer) => k\n if k >= 0:\n return k\n \"Type a cell from A1 to F9, like B3.\" ^0\n\ndef set_cell(state):\n ask_cell(\"cell> \") => k\n if k == -1:\n \"Cancelled.\" ^0\n return\n trim(input(\"content of \" + sheet.cell_name(k) + \" (a number, a label, or =formula)> \")) => text\n if text == \"\":\n \"Cancelled - use 2) to empty a cell.\" ^0\n return\n if len(text) > 60:\n \"Keep a cell to 60 characters.\" ^0\n return\n if text[0] == \"=\":\n sheet.checked(text[1:len(text)]) => c\n if c[0] != \"\":\n (\"Not a formula: \" + c[0] + \". Nothing was changed.\") ^0\n return\n text => state[0][k]\n update(state, k)\n\ndef update(state, k):\n sheet.recalculated(state[0]) => res\n res[0] => state[1]\n res[1] => state[2]\n sheet.cell_name(k) + \" = \" + shown(state[1][k]) => what\n if state[0][k] == \"\":\n sheet.cell_name(k) + \" is empty now\" => what\n (what + \"; \" + str(len(state[2])) + \" formula cell(s) worked out again.\") ^0\n 0 => stuck\n for j in [0:53]:\n if state[0][j] != \"\" and state[0][j][0] == \"=\" and state[1][j][0] == \"e\" and state[1][j][1] == \"#CYCLE\":\n stuck + 1 => stuck\n if stuck > 0:\n (str(stuck) + \" formula cell(s) are in a cycle, or read one - they show #CYCLE until it is broken.\") ^0\n\ndef clear_cell(state):\n ask_cell(\"cell to empty> \") => k\n if k == -1:\n \"Cancelled.\" ^0\n return\n \"\" => state[0][k]\n update(state, k)\n\ndef order(state):\n if len(state[2]) == 0:\n \"No formula has been worked out yet.\" ^0\n else:\n \"\" => s\n for k in state[2]:\n if s != \"\":\n s + \", \" => s\n s + sheet.cell_name(k) => s\n (\"Worked out in this order: \" + s + \".\") ^0\n \"\" => stuck\n for j in [0:53]:\n if state[0][j] != \"\" and state[0][j][0] == \"=\" and state[1][j][1] == \"#CYCLE\":\n if stuck != \"\":\n stuck + \", \" => stuck\n stuck + sheet.cell_name(j) => stuck\n if stuck != \"\":\n (\"In a cycle, or reading one: \" + stuck + \".\") ^0\n\ndef sample(state):\n [\"\"] * 54 => cells\n [[\"A1\", \"Item\"], [\"B1\", \"Price\"], [\"C1\", \"Qty\"], [\"D1\", \"Total\"],\n [\"A2\", \"Paper\"], [\"B2\", \"4.5\"], [\"C2\", \"3\"], [\"D2\", \"=B2*C2\"],\n [\"A3\", \"Pens\"], [\"B3\", \"1.2\"], [\"C3\", \"10\"], [\"D3\", \"=B3*C3\"],\n [\"A4\", \"Folders\"], [\"B4\", \"2.75\"], [\"C4\", \"4\"], [\"D4\", \"=B4*C4\"],\n [\"A6\", \"Subtotal\"], [\"D6\", \"=SUM(D2:D4)\"],\n [\"A7\", \"Tax rate\"], [\"B7\", \"0.08\"], [\"D7\", \"=D6*B7\"],\n [\"A8\", \"Total\"], [\"D8\", \"=D6+D7\"],\n [\"A9\", \"Average\"], [\"D9\", \"=AVG(D2:D4)\"]] => entries\n for e in entries:\n e[1] => cells[sheet.cell_index(e[0])]\n cells => state[0]\n sheet.recalculated(cells) => res\n res[0] => state[1]\n res[1] => state[2]\n \"A small order: three items, their totals, tax at 8% and an average.\" ^0\n\n\"== Mini spreadsheet ==\" ^0\n\"Cells A1 to F9 hold numbers, labels, or formulas such as =B2*C2 or =SUM(D2:D4).\" ^0\n# [cell texts, cell values, the order formulas were worked out]\n[[\"\"] * 54, [], []] => state\nsheet.recalculated(state[0]) => first\nfirst[0] => state[1]\nTrue => running\nwhile running:\n \"\" ^0\n \"1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\" ^0\n trim(input(\"choice> \")) => choice\n if choice == \"1\":\n set_cell(state)\n elif choice == \"2\":\n clear_cell(state)\n elif choice == \"3\":\n grid(state[0], state[1], False)\n elif choice == \"4\":\n grid(state[0], state[1], True)\n elif choice == \"5\":\n order(state)\n elif choice == \"6\":\n sample(state)\n grid(state[0], state[1], False)\n elif choice == \"7\":\n False => running\n else:\n \"Pick a number from 1 to 7.\" ^0\n\"Bye.\" ^0\n", "python": "import frac\nimport sheet\n\ndef trim(s):\n i = 0\n j = len(s)\n while i < j and s[i] == \" \":\n i = i + 1\n while j > i and s[j - 1] == \" \":\n j = j - 1\n return s[i:j]\n\ndef shown(v):\n if v[0] == \"e\":\n return v[1]\n if v[0] == \"t\":\n if len(v[1]) > 10:\n return v[1][0:9] + \"~\"\n return v[1]\n s = frac.decimal(v[1], 2)\n if len(s) > 6 and s[0:6] == \"about \":\n s = \"~\" + s[6:len(s)]\n if len(s) > 10:\n return \"#WIDE\"\n return s\n\ndef grid(cells, vals, formulas):\n head = \" \"\n for c in range(0, 6):\n h = \" \" + \"ABCDEF\"[c]\n head = head + h[len(h) - 10:len(h)] + \" \"\n print(trim_right(head))\n for r in range(0, 9):\n line = \" \" + str(r + 1) + \" \"\n for c in range(0, 6):\n k = r * 6 + c\n if formulas:\n s = cells[k]\n if len(s) > 10:\n s = s[0:9] + \"~\"\n else:\n s = shown(vals[k])\n if formulas or vals[k][0] == \"t\":\n while len(s) < 10:\n s = s + \" \"\n else:\n while len(s) < 10:\n s = \" \" + s\n line = line + s + \" \"\n print(trim_right(line))\n\ndef trim_right(s):\n j = len(s)\n while j > 0 and s[j - 1] == \" \":\n j = j - 1\n return s[0:j]\n\ndef ask_cell(prompt):\n while True:\n answer = trim(input(prompt))\n if answer == \"\":\n return -1\n k = sheet.cell_index(answer)\n if k >= 0:\n return k\n print(\"Type a cell from A1 to F9, like B3.\")\n\ndef set_cell(state):\n k = ask_cell(\"cell> \")\n if k == -1:\n print(\"Cancelled.\")\n return\n text = trim(input(\"content of \" + sheet.cell_name(k) + \" (a number, a label, or =formula)> \"))\n if text == \"\":\n print(\"Cancelled - use 2) to empty a cell.\")\n return\n if len(text) > 60:\n print(\"Keep a cell to 60 characters.\")\n return\n if text[0] == \"=\":\n c = sheet.checked(text[1:len(text)])\n if c[0] != \"\":\n print(\"Not a formula: \" + c[0] + \". Nothing was changed.\")\n return\n state[0][k] = text\n update(state, k)\n\ndef update(state, k):\n res = sheet.recalculated(state[0])\n state[1] = res[0]\n state[2] = res[1]\n what = sheet.cell_name(k) + \" = \" + shown(state[1][k])\n if state[0][k] == \"\":\n what = sheet.cell_name(k) + \" is empty now\"\n print(what + \"; \" + str(len(state[2])) + \" formula cell(s) worked out again.\")\n stuck = 0\n for j in range(0, 54):\n if state[0][j] != \"\" and state[0][j][0] == \"=\" and state[1][j][0] == \"e\" and state[1][j][1] == \"#CYCLE\":\n stuck = stuck + 1\n if stuck > 0:\n print(str(stuck) + \" formula cell(s) are in a cycle, or read one - they show #CYCLE until it is broken.\")\n\ndef clear_cell(state):\n k = ask_cell(\"cell to empty> \")\n if k == -1:\n print(\"Cancelled.\")\n return\n state[0][k] = \"\"\n update(state, k)\n\ndef order(state):\n if len(state[2]) == 0:\n print(\"No formula has been worked out yet.\")\n else:\n s = \"\"\n for k in state[2]:\n if s != \"\":\n s = s + \", \"\n s = s + sheet.cell_name(k)\n print(\"Worked out in this order: \" + s + \".\")\n stuck = \"\"\n for j in range(0, 54):\n if state[0][j] != \"\" and state[0][j][0] == \"=\" and state[1][j][1] == \"#CYCLE\":\n if stuck != \"\":\n stuck = stuck + \", \"\n stuck = stuck + sheet.cell_name(j)\n if stuck != \"\":\n print(\"In a cycle, or reading one: \" + stuck + \".\")\n\ndef sample(state):\n cells = [\"\"] * 54\n entries = [[\"A1\", \"Item\"], [\"B1\", \"Price\"], [\"C1\", \"Qty\"], [\"D1\", \"Total\"], [\"A2\", \"Paper\"], [\"B2\", \"4.5\"], [\"C2\", \"3\"], [\"D2\", \"=B2*C2\"], [\"A3\", \"Pens\"], [\"B3\", \"1.2\"], [\"C3\", \"10\"], [\"D3\", \"=B3*C3\"], [\"A4\", \"Folders\"], [\"B4\", \"2.75\"], [\"C4\", \"4\"], [\"D4\", \"=B4*C4\"], [\"A6\", \"Subtotal\"], [\"D6\", \"=SUM(D2:D4)\"], [\"A7\", \"Tax rate\"], [\"B7\", \"0.08\"], [\"D7\", \"=D6*B7\"], [\"A8\", \"Total\"], [\"D8\", \"=D6+D7\"], [\"A9\", \"Average\"], [\"D9\", \"=AVG(D2:D4)\"]]\n for e in entries:\n cells[sheet.cell_index(e[0])] = e[1]\n state[0] = cells\n res = sheet.recalculated(cells)\n state[1] = res[0]\n state[2] = res[1]\n print(\"A small order: three items, their totals, tax at 8% and an average.\")\n\nprint(\"== Mini spreadsheet ==\")\nprint(\"Cells A1 to F9 hold numbers, labels, or formulas such as =B2*C2 or =SUM(D2:D4).\")\nstate = [[\"\"] * 54, [], []]\nfirst = sheet.recalculated(state[0])\nstate[1] = first[0]\nrunning = True\nwhile running:\n print(\"\")\n print(\"1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\")\n choice = trim(input(\"choice> \"))\n if choice == \"1\":\n set_cell(state)\n elif choice == \"2\":\n clear_cell(state)\n elif choice == \"3\":\n grid(state[0], state[1], False)\n elif choice == \"4\":\n grid(state[0], state[1], True)\n elif choice == \"5\":\n order(state)\n elif choice == \"6\":\n sample(state)\n grid(state[0], state[1], False)\n elif choice == \"7\":\n running = False\n else:\n print(\"Pick a number from 1 to 7.\")\nprint(\"Bye.\")\n" }, { "name": "sheet.eml", "eml": "# P056 mini spreadsheet - formulas and recalculation. The sheet has columns\n# A to F and rows 1 to 9; cell k (0 to 53) is column k % 6, row k / 6.\n# A cell holds text as typed: \"\" (empty), a number, a formula starting\n# with \"=\", or any other text (a label). A value is [\"n\", fraction],\n# [\"t\", text] or [\"e\", error].\nimport frac\n\ndef cell_name(k):\n return \"ABCDEF\"[k % 6] + str(int(k / 6) + 1)\n\ndef cell_index(s):\n # \"B3\" or \"b3\" as 0 to 53, or -1.\n if len(s) != 2:\n return -1\n -1 => col\n for c in [0:5]:\n if s[0] == \"ABCDEF\"[c] or s[0] == \"abcdef\"[c]:\n c => col\n if col == -1 or not (s[1] >= \"1\" and s[1] <= \"9\"):\n return -1\n return (int(s[1]) - 1) * 6 + col\n\ndef tokens(f):\n # The formula text after \"=\" as tokens: [\"num\", fraction], [\"cell\", k],\n # [\"fn\", name], [\"op\", \"+\"] and so on; or [[\"bad\", why]].\n [] => out\n 0 => i\n while i < len(f):\n f[i] => c\n if c == \" \":\n i + 1 => i\n elif c == \"+\" or c == \"-\" or c == \"*\" or c == \"/\" or c == \"(\" or c == \")\" or c == \":\" or c == \",\":\n out + [[\"op\", c]] => out\n i + 1 => i\n elif c >= \"0\" and c <= \"9\" or c == \".\":\n i => j\n while j < len(f) and (f[j] >= \"0\" and f[j] <= \"9\" or f[j] == \".\"):\n j + 1 => j\n frac.parse(f[i:j]) => x\n if len(x) == 0:\n return [[\"bad\", \"the number \" + f[i:j]]]\n out + [[\"num\", x]] => out\n j => i\n elif (c >= \"A\" and c <= \"Z\") or (c >= \"a\" and c <= \"z\"):\n i => j\n while j < len(f) and ((f[j] >= \"A\" and f[j] <= \"Z\") or (f[j] >= \"a\" and f[j] <= \"z\") or (f[j] >= \"0\" and f[j] <= \"9\")):\n j + 1 => j\n f[i:j] => w\n cell_index(w) => k\n if k >= 0:\n out + [[\"cell\", k]] => out\n else:\n \"\" => up\n for ch in w:\n ch => u\n for q in [0:25]:\n if ch == \"abcdefghijklmnopqrstuvwxyz\"[q]:\n \"ABCDEFGHIJKLMNOPQRSTUVWXYZ\"[q] => u\n up + u => up\n if up == \"SUM\" or up == \"MIN\" or up == \"MAX\" or up == \"AVG\":\n out + [[\"fn\", up]] => out\n else:\n return [[\"bad\", w + \", which is not a cell from A1 to F9 or one of SUM, MIN, MAX, AVG\"]]\n j => i\n else:\n return [[\"bad\", \"the character \" + c]]\n return out\n\n# The parser walks the tokens with a position kept in p[0]. Each step\n# returns a value, given the values of all cells so far (vals); parsing\n# alone (vals = []) only checks the shape and collects the cells read.\n\ndef peek(ts, p):\n if p[0] < len(ts):\n return ts[p[0]]\n return [\"end\", \"\"]\n\ndef is_op(t, c):\n return t[0] == \"op\" and t[1] == c\n\ndef arith(a, b, op):\n if a[0] == \"e\":\n return a\n if b[0] == \"e\":\n return b\n if a[0] == \"t\" or b[0] == \"t\":\n return [\"e\", \"#TEXT\"]\n if op == \"+\":\n return [\"n\", frac.plus(a[1], b[1])]\n if op == \"-\":\n return [\"n\", frac.minus(a[1], b[1])]\n if op == \"*\":\n return [\"n\", frac.times(a[1], b[1])]\n if frac.is_zero(b[1]):\n return [\"e\", \"#DIV/0\"]\n return [\"n\", frac.over(a[1], b[1])]\n\ndef read_cell(k, vals, refs):\n # refs is [the list of cells read so far], kept in a one-item list so\n # every call adds to the same one.\n refs[0] + [k] => refs[0]\n if len(vals) == 0:\n return [\"n\", [0, 1]]\n vals[k] => v\n if v[0] == \"t\" and v[1] == \"\":\n return [\"n\", [0, 1]]\n return v\n\ndef expr(ts, p, vals, refs):\n term(ts, p, vals, refs) => v\n while is_op(peek(ts, p), \"+\") or is_op(peek(ts, p), \"-\"):\n peek(ts, p)[1] => op\n p[0] + 1 => p[0]\n arith(v, term(ts, p, vals, refs), op) => v\n return v\n\ndef term(ts, p, vals, refs):\n factor(ts, p, vals, refs) => v\n while is_op(peek(ts, p), \"*\") or is_op(peek(ts, p), \"/\"):\n peek(ts, p)[1] => op\n p[0] + 1 => p[0]\n arith(v, factor(ts, p, vals, refs), op) => v\n return v\n\ndef factor(ts, p, vals, refs):\n peek(ts, p) => t\n if is_op(t, \"-\"):\n p[0] + 1 => p[0]\n return arith([\"n\", [0, 1]], factor(ts, p, vals, refs), \"-\")\n if t[0] == \"num\":\n p[0] + 1 => p[0]\n return [\"n\", t[1]]\n if t[0] == \"cell\":\n p[0] + 1 => p[0]\n return read_cell(t[1], vals, refs)\n if is_op(t, \"(\"):\n p[0] + 1 => p[0]\n expr(ts, p, vals, refs) => v\n if not is_op(peek(ts, p), \")\"):\n [\"bad\", \"a ( without its )\"] => p[1]\n else:\n p[0] + 1 => p[0]\n return v\n if t[0] == \"fn\":\n p[0] + 1 => p[0]\n return function(t[1], ts, p, vals, refs)\n [\"bad\", \"something missing where a number, a cell or ( should be\"] => p[1]\n return [\"e\", \"#BAD\"]\n\ndef function(fname, ts, p, vals, refs):\n # SUM, MIN, MAX or AVG of cells and ranges: (A1:A5) or (A1, B2, C1:C3).\n if not is_op(peek(ts, p), \"(\"):\n [\"bad\", fname + \" without ( after it\"] => p[1]\n return [\"e\", \"#BAD\"]\n p[0] + 1 => p[0]\n [] => cells\n while True:\n peek(ts, p) => a\n if a[0] != \"cell\":\n [\"bad\", fname + \"( with something other than cells and ranges in it, where \" + fname + \"(A1:A5) would do\"] => p[1]\n return [\"e\", \"#BAD\"]\n p[0] + 1 => p[0]\n if is_op(peek(ts, p), \":\"):\n p[0] + 1 => p[0]\n peek(ts, p) => b\n if b[0] != \"cell\":\n [\"bad\", \"a range with no cell after its :\"] => p[1]\n return [\"e\", \"#BAD\"]\n p[0] + 1 => p[0]\n a[1] % 6 => c1\n b[1] % 6 => c2\n int(a[1] / 6) => r1\n int(b[1] / 6) => r2\n if c2 < c1:\n c1 => t\n c2 => c1\n t => c2\n if r2 < r1:\n r1 => t\n r2 => r1\n t => r2\n for r in [r1:r2]:\n for c in [c1:c2]:\n cells + [r * 6 + c] => cells\n else:\n cells + [a[1]] => cells\n if is_op(peek(ts, p), \",\"):\n p[0] + 1 => p[0]\n elif is_op(peek(ts, p), \")\"):\n p[0] + 1 => p[0]\n break\n else:\n [\"bad\", fname + \"( with no , between two cells or no ) at the end\"] => p[1]\n return [\"e\", \"#BAD\"]\n # Empty cells and labels are left out, as spreadsheets do; an error in\n # any cell makes the whole result that error.\n [] => nums\n for k in cells:\n read_cell(k, vals, refs) => v\n if v[0] == \"e\":\n return v\n if v[0] == \"n\" and not (len(vals) > 0 and vals[k][0] == \"t\"):\n nums + [v[1]] => nums\n if len(vals) == 0:\n return [\"n\", [0, 1]]\n if fname == \"SUM\" or fname == \"AVG\":\n [0, 1] => s\n for x in nums:\n frac.plus(s, x) => s\n if fname == \"SUM\":\n return [\"n\", s]\n if len(nums) == 0:\n return [\"e\", \"#DIV/0\"]\n return [\"n\", frac.over(s, [len(nums), 1])]\n if len(nums) == 0:\n return [\"n\", [0, 1]]\n nums[0] => best\n for x in nums:\n if fname == \"MIN\" and frac.less(x, best):\n x => best\n if fname == \"MAX\" and frac.less(best, x):\n x => best\n return [\"n\", best]\n\ndef checked(text):\n # Parses a formula (\"=\" already taken off): [problem or \"\", the cells it\n # reads, the tokens].\n tokens(text) => ts\n if len(ts) > 0 and ts[0][0] == \"bad\":\n return [\"it has \" + ts[0][1], [], []]\n if len(ts) == 0:\n return [\"it is empty\", [], []]\n [0, \"\"] => p\n [[]] => refs\n expr(ts, p, [], refs)\n if p[1] != \"\":\n return [\"it has \" + p[1][1], [], []]\n if p[0] < len(ts):\n return [\"something is left over after the formula ends\", [], []]\n return [\"\", refs[0], ts]\n\ndef value_of(ts, vals):\n [0, \"\"] => p\n [[]] => refs\n return expr(ts, p, vals, refs)\n\ndef recalculated(cells):\n # Every cell's value, and the formula cells in the order they were\n # worked out. The order is Kahn's algorithm, as in the corpus case\n # topological-sort: a formula is ready once every formula it reads is\n # done; formulas never ready are caught in a cycle, or read one that is.\n [] => vals\n [] => formulas\n for k in [0:53]:\n cells[k] => s\n if s == \"\":\n vals + [[\"t\", \"\"]] => vals\n elif s[0] == \"=\":\n vals + [[\"e\", \"#CYCLE\"]] => vals\n formulas + [k] => formulas\n else:\n frac.parse(s) => x\n if len(x) > 0:\n vals + [[\"n\", x]] => vals\n else:\n vals + [[\"t\", s]] => vals\n # reads[k]: the formula cells formula k reads, once each\n {} => reads\n {} => waiting\n for k in formulas:\n checked(cells[k][1:len(cells[k])]) => c\n [] => mine\n for r in c[1]:\n if cells[r] != \"\" and cells[r][0] == \"=\":\n False => seen\n for m in mine:\n if m == r:\n True => seen\n if not seen:\n mine + [r] => mine\n mine => reads[k]\n len(mine) => waiting[k]\n [] => ready\n for k in formulas:\n if waiting[k] == 0:\n ready + [k] => ready\n [] => order\n 0 => head\n while head < len(ready):\n ready[head] => k\n head + 1 => head\n order + [k] => order\n tokens(cells[k][1:len(cells[k])]) => ts\n value_of(ts, vals) => vals[k]\n for j in formulas:\n for r in reads[j]:\n if r == k:\n waiting[j] - 1 => waiting[j]\n if waiting[j] == 0:\n ready + [j] => ready\n return [vals, order]\n", "python": "import frac\n\ndef cell_name(k):\n return \"ABCDEF\"[k % 6] + str(int(k / 6) + 1)\n\ndef cell_index(s):\n if len(s) != 2:\n return -1\n col = -1\n for c in range(0, 6):\n if s[0] == \"ABCDEF\"[c] or s[0] == \"abcdef\"[c]:\n col = c\n if col == -1 or not (s[1] >= \"1\" and s[1] <= \"9\"):\n return -1\n return (int(s[1]) - 1) * 6 + col\n\ndef tokens(f):\n out = []\n i = 0\n while i < len(f):\n c = f[i]\n if c == \" \":\n i = i + 1\n elif c == \"+\" or c == \"-\" or c == \"*\" or c == \"/\" or c == \"(\" or c == \")\" or c == \":\" or c == \",\":\n out = out + [[\"op\", c]]\n i = i + 1\n elif c >= \"0\" and c <= \"9\" or c == \".\":\n j = i\n while j < len(f) and (f[j] >= \"0\" and f[j] <= \"9\" or f[j] == \".\"):\n j = j + 1\n x = frac.parse(f[i:j])\n if len(x) == 0:\n return [[\"bad\", \"the number \" + f[i:j]]]\n out = out + [[\"num\", x]]\n i = j\n elif c >= \"A\" and c <= \"Z\" or c >= \"a\" and c <= \"z\":\n j = i\n while j < len(f) and (f[j] >= \"A\" and f[j] <= \"Z\" or f[j] >= \"a\" and f[j] <= \"z\" or f[j] >= \"0\" and f[j] <= \"9\"):\n j = j + 1\n w = f[i:j]\n k = cell_index(w)\n if k >= 0:\n out = out + [[\"cell\", k]]\n else:\n up = \"\"\n for ch in w:\n u = ch\n for q in range(0, 26):\n if ch == \"abcdefghijklmnopqrstuvwxyz\"[q]:\n u = \"ABCDEFGHIJKLMNOPQRSTUVWXYZ\"[q]\n up = up + u\n if up == \"SUM\" or up == \"MIN\" or up == \"MAX\" or up == \"AVG\":\n out = out + [[\"fn\", up]]\n else:\n return [[\"bad\", w + \", which is not a cell from A1 to F9 or one of SUM, MIN, MAX, AVG\"]]\n i = j\n else:\n return [[\"bad\", \"the character \" + c]]\n return out\n\ndef peek(ts, p):\n if p[0] < len(ts):\n return ts[p[0]]\n return [\"end\", \"\"]\n\ndef is_op(t, c):\n return t[0] == \"op\" and t[1] == c\n\ndef arith(a, b, op):\n if a[0] == \"e\":\n return a\n if b[0] == \"e\":\n return b\n if a[0] == \"t\" or b[0] == \"t\":\n return [\"e\", \"#TEXT\"]\n if op == \"+\":\n return [\"n\", frac.plus(a[1], b[1])]\n if op == \"-\":\n return [\"n\", frac.minus(a[1], b[1])]\n if op == \"*\":\n return [\"n\", frac.times(a[1], b[1])]\n if frac.is_zero(b[1]):\n return [\"e\", \"#DIV/0\"]\n return [\"n\", frac.over(a[1], b[1])]\n\ndef read_cell(k, vals, refs):\n refs[0] = refs[0] + [k]\n if len(vals) == 0:\n return [\"n\", [0, 1]]\n v = vals[k]\n if v[0] == \"t\" and v[1] == \"\":\n return [\"n\", [0, 1]]\n return v\n\ndef expr(ts, p, vals, refs):\n v = term(ts, p, vals, refs)\n while is_op(peek(ts, p), \"+\") or is_op(peek(ts, p), \"-\"):\n op = peek(ts, p)[1]\n p[0] = p[0] + 1\n v = arith(v, term(ts, p, vals, refs), op)\n return v\n\ndef term(ts, p, vals, refs):\n v = factor(ts, p, vals, refs)\n while is_op(peek(ts, p), \"*\") or is_op(peek(ts, p), \"/\"):\n op = peek(ts, p)[1]\n p[0] = p[0] + 1\n v = arith(v, factor(ts, p, vals, refs), op)\n return v\n\ndef factor(ts, p, vals, refs):\n t = peek(ts, p)\n if is_op(t, \"-\"):\n p[0] = p[0] + 1\n return arith([\"n\", [0, 1]], factor(ts, p, vals, refs), \"-\")\n if t[0] == \"num\":\n p[0] = p[0] + 1\n return [\"n\", t[1]]\n if t[0] == \"cell\":\n p[0] = p[0] + 1\n return read_cell(t[1], vals, refs)\n if is_op(t, \"(\"):\n p[0] = p[0] + 1\n v = expr(ts, p, vals, refs)\n if not is_op(peek(ts, p), \")\"):\n p[1] = [\"bad\", \"a ( without its )\"]\n else:\n p[0] = p[0] + 1\n return v\n if t[0] == \"fn\":\n p[0] = p[0] + 1\n return function(t[1], ts, p, vals, refs)\n p[1] = [\"bad\", \"something missing where a number, a cell or ( should be\"]\n return [\"e\", \"#BAD\"]\n\ndef function(fname, ts, p, vals, refs):\n if not is_op(peek(ts, p), \"(\"):\n p[1] = [\"bad\", fname + \" without ( after it\"]\n return [\"e\", \"#BAD\"]\n p[0] = p[0] + 1\n cells = []\n while True:\n a = peek(ts, p)\n if a[0] != \"cell\":\n p[1] = [\"bad\", fname + \"( with something other than cells and ranges in it, where \" + fname + \"(A1:A5) would do\"]\n return [\"e\", \"#BAD\"]\n p[0] = p[0] + 1\n if is_op(peek(ts, p), \":\"):\n p[0] = p[0] + 1\n b = peek(ts, p)\n if b[0] != \"cell\":\n p[1] = [\"bad\", \"a range with no cell after its :\"]\n return [\"e\", \"#BAD\"]\n p[0] = p[0] + 1\n c1 = a[1] % 6\n c2 = b[1] % 6\n r1 = int(a[1] / 6)\n r2 = int(b[1] / 6)\n if c2 < c1:\n t = c1\n c1 = c2\n c2 = t\n if r2 < r1:\n t = r1\n r1 = r2\n r2 = t\n for r in range(r1, r2+1):\n for c in range(c1, c2+1):\n cells = cells + [r * 6 + c]\n else:\n cells = cells + [a[1]]\n if is_op(peek(ts, p), \",\"):\n p[0] = p[0] + 1\n elif is_op(peek(ts, p), \")\"):\n p[0] = p[0] + 1\n break\n else:\n p[1] = [\"bad\", fname + \"( with no , between two cells or no ) at the end\"]\n return [\"e\", \"#BAD\"]\n nums = []\n for k in cells:\n v = read_cell(k, vals, refs)\n if v[0] == \"e\":\n return v\n if v[0] == \"n\" and not (len(vals) > 0 and vals[k][0] == \"t\"):\n nums = nums + [v[1]]\n if len(vals) == 0:\n return [\"n\", [0, 1]]\n if fname == \"SUM\" or fname == \"AVG\":\n s = [0, 1]\n for x in nums:\n s = frac.plus(s, x)\n if fname == \"SUM\":\n return [\"n\", s]\n if len(nums) == 0:\n return [\"e\", \"#DIV/0\"]\n return [\"n\", frac.over(s, [len(nums), 1])]\n if len(nums) == 0:\n return [\"n\", [0, 1]]\n best = nums[0]\n for x in nums:\n if fname == \"MIN\" and frac.less(x, best):\n best = x\n if fname == \"MAX\" and frac.less(best, x):\n best = x\n return [\"n\", best]\n\ndef checked(text):\n ts = tokens(text)\n if len(ts) > 0 and ts[0][0] == \"bad\":\n return [\"it has \" + ts[0][1], [], []]\n if len(ts) == 0:\n return [\"it is empty\", [], []]\n p = [0, \"\"]\n refs = [[]]\n expr(ts, p, [], refs)\n if p[1] != \"\":\n return [\"it has \" + p[1][1], [], []]\n if p[0] < len(ts):\n return [\"something is left over after the formula ends\", [], []]\n return [\"\", refs[0], ts]\n\ndef value_of(ts, vals):\n p = [0, \"\"]\n refs = [[]]\n return expr(ts, p, vals, refs)\n\ndef recalculated(cells):\n vals = []\n formulas = []\n for k in range(0, 54):\n s = cells[k]\n if s == \"\":\n vals = vals + [[\"t\", \"\"]]\n elif s[0] == \"=\":\n vals = vals + [[\"e\", \"#CYCLE\"]]\n formulas = formulas + [k]\n else:\n x = frac.parse(s)\n if len(x) > 0:\n vals = vals + [[\"n\", x]]\n else:\n vals = vals + [[\"t\", s]]\n reads = {}\n waiting = {}\n for k in formulas:\n c = checked(cells[k][1:len(cells[k])])\n mine = []\n for r in c[1]:\n if cells[r] != \"\" and cells[r][0] == \"=\":\n seen = False\n for m in mine:\n if m == r:\n seen = True\n if not seen:\n mine = mine + [r]\n reads[k] = mine\n waiting[k] = len(mine)\n ready = []\n for k in formulas:\n if waiting[k] == 0:\n ready = ready + [k]\n order = []\n head = 0\n while head < len(ready):\n k = ready[head]\n head = head + 1\n order = order + [k]\n ts = tokens(cells[k][1:len(cells[k])])\n vals[k] = value_of(ts, vals)\n for j in formulas:\n for r in reads[j]:\n if r == k:\n waiting[j] = waiting[j] - 1\n if waiting[j] == 0:\n ready = ready + [j]\n return [vals, order]\n" }, { "name": "frac.eml", "eml": "# P056 mini spreadsheet - exact fractions, from P007 (calculator) by way of\n# P038 and P044.\n# A number is a list [n, d]: n / d in lowest terms with d > 0. Integers have\n# no size limit, but EML has no //, and a / b goes through a float that cannot\n# hold a large quotient exactly, so whole-number division is written out.\n\ndef quotient(a, b):\n # a // b for whole numbers a >= 0 and b > 0, exact at any size. Long\n # division by doubling: take away the largest b * 2^k that still fits.\n 0 => q\n while a >= b:\n b => m\n 1 => k\n while m + m <= a:\n m + m => m\n k + k => k\n a - m => a\n q + k => q\n return q\n\ndef gcd(a, b):\n while b != 0:\n a % b => r\n b => a\n r => b\n return a\n\ndef make(n, d):\n # n / d in lowest terms with a positive denominator (d != 0).\n if d < 0:\n 0 - n => n\n 0 - d => d\n abs(n) => a\n gcd(a, d) => g\n if n < 0:\n return [0 - quotient(a, g), quotient(d, g)]\n return [quotient(a, g), quotient(d, g)]\n\ndef plus(x, y):\n return make(x[0] * y[1] + y[0] * x[1], x[1] * y[1])\n\ndef minus(x, y):\n return make(x[0] * y[1] - y[0] * x[1], x[1] * y[1])\n\ndef times(x, y):\n return make(x[0] * y[0], x[1] * y[1])\n\ndef over(x, y):\n # x / y; the caller has checked that y is not zero.\n return make(x[0] * y[1], x[1] * y[0])\n\ndef is_zero(x):\n return x[0] == 0\n\ndef digits_value(s):\n # The value of a string of 1 to 9 digits, otherwise -1.\n if s == \"\" or len(s) > 9:\n return -1\n 0 => n\n for c in s:\n if not (c in \"0123456789\"):\n return -1\n n * 10 + int(c) => n\n return n\n\ndef parse(s):\n # \"3\", \"-2\", \"3/4\", \"-0.25\" as a fraction; [] if it is not a number.\n 1 => sign\n if len(s) > 0 and s[0] == \"-\":\n -1 => sign\n s[1:len(s)] => s\n 0 => k\n while k < len(s) and s[k] != \"/\" and s[k] != \".\":\n k + 1 => k\n if k == len(s):\n digits_value(s) => n\n if n < 0:\n return []\n return make(sign * n, 1)\n digits_value(s[0:k]) => whole\n s[k + 1:len(s)] => rest\n digits_value(rest) => part\n if whole < 0 or part < 0:\n return []\n if s[k] == \"/\":\n if part == 0:\n return []\n return make(sign * whole, part)\n # a decimal point: 0.25 is 25 / 100\n 1 => scale\n for c in rest:\n scale * 10 => scale\n return make(sign * (whole * scale + part), scale)\n\ndef less(x, y):\n return x[0] * y[1] < y[0] * x[1]\n\ndef decimal(x, places):\n # x to the given number of decimal places, halves rounded away from zero,\n # with \"about \" in front when the value does not end there exactly.\n \"\" => sign\n abs(x[0]) => n\n if x[0] < 0:\n \"-\" => sign\n 1 => scale\n for k in [1:places]:\n scale * 10 => scale\n quotient(2 * n * scale + x[1], 2 * x[1]) => t\n \"\" => about\n if (n * scale) % x[1] != 0:\n \"about \" => about\n str(quotient(t, scale)) => whole\n str(t % scale) => part\n while len(part) < places:\n \"0\" + part => part\n # drop trailing zeros of an exact value\n if about == \"\":\n while len(part) > 0 and part[len(part) - 1] == \"0\":\n part[0:len(part) - 1] => part\n if t == 0:\n \"\" => sign\n if part == \"\":\n return about + sign + whole\n return about + sign + whole + \".\" + part\n\ndef text(x):\n # \"3\", \"-3\", \"3/4\", \"-3/4\".\n if x[1] == 1:\n return str(x[0])\n return str(x[0]) + \"/\" + str(x[1])\n", "python": "def quotient(a, b):\n q = 0\n while a >= b:\n m = b\n k = 1\n while m + m <= a:\n m = m + m\n k = k + k\n a = a - m\n q = q + k\n return q\n\ndef gcd(a, b):\n while b != 0:\n r = a % b\n a = b\n b = r\n return a\n\ndef make(n, d):\n if d < 0:\n n = 0 - n\n d = 0 - d\n a = abs(n)\n g = gcd(a, d)\n if n < 0:\n return [0 - quotient(a, g), quotient(d, g)]\n return [quotient(a, g), quotient(d, g)]\n\ndef plus(x, y):\n return make(x[0] * y[1] + y[0] * x[1], x[1] * y[1])\n\ndef minus(x, y):\n return make(x[0] * y[1] - y[0] * x[1], x[1] * y[1])\n\ndef times(x, y):\n return make(x[0] * y[0], x[1] * y[1])\n\ndef over(x, y):\n return make(x[0] * y[1], x[1] * y[0])\n\ndef is_zero(x):\n return x[0] == 0\n\ndef digits_value(s):\n if s == \"\" or len(s) > 9:\n return -1\n n = 0\n for c in s:\n if not c in \"0123456789\":\n return -1\n n = n * 10 + int(c)\n return n\n\ndef parse(s):\n sign = 1\n if len(s) > 0 and s[0] == \"-\":\n sign = -1\n s = s[1:len(s)]\n k = 0\n while k < len(s) and s[k] != \"/\" and s[k] != \".\":\n k = k + 1\n if k == len(s):\n n = digits_value(s)\n if n < 0:\n return []\n return make(sign * n, 1)\n whole = digits_value(s[0:k])\n rest = s[k + 1:len(s)]\n part = digits_value(rest)\n if whole < 0 or part < 0:\n return []\n if s[k] == \"/\":\n if part == 0:\n return []\n return make(sign * whole, part)\n scale = 1\n for c in rest:\n scale = scale * 10\n return make(sign * (whole * scale + part), scale)\n\ndef less(x, y):\n return x[0] * y[1] < y[0] * x[1]\n\ndef decimal(x, places):\n sign = \"\"\n n = abs(x[0])\n if x[0] < 0:\n sign = \"-\"\n scale = 1\n for k in range(1, places+1):\n scale = scale * 10\n t = quotient(2 * n * scale + x[1], 2 * x[1])\n about = \"\"\n if n * scale % x[1] != 0:\n about = \"about \"\n whole = str(quotient(t, scale))\n part = str(t % scale)\n while len(part) < places:\n part = \"0\" + part\n if about == \"\":\n while len(part) > 0 and part[len(part) - 1] == \"0\":\n part = part[0:len(part) - 1]\n if t == 0:\n sign = \"\"\n if part == \"\":\n return about + sign + whole\n return about + sign + whole + \".\" + part\n\ndef text(x):\n if x[1] == 1:\n return str(x[0])\n return str(x[0]) + \"/\" + str(x[1])\n" } ], "sessions": [ { "name": "bad-input", "input": "0\nx\n1\nG1\nA0\n\n1\nA1\n\n1\nA1\n=1+\n1\nA1\n=SUM(B1\n1\nA1\n=A1+1\n1\nA2\n=B1/C1\n1\nA3\nlabel\n1\nA4\n=A3*2\n1\nA5\n=SUM(A3:A4, B9)\n1\nA6\n=1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1\n1\nA6\n=AVG(B1:B9)\n2\nA1\n3\n4\n5\n7\n", "screen": "== Mini spreadsheet ==\nCells A1 to F9 hold numbers, labels, or formulas such as =B2*C2 or =SUM(D2:D4).\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 0\nPick a number from 1 to 7.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> x\nPick a number from 1 to 7.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> G1\nType a cell from A1 to F9, like B3.\ncell> A0\nType a cell from A1 to F9, like B3.\ncell> \nCancelled.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> A1\ncontent of A1 (a number, a label, or =formula)> \nCancelled - use 2) to empty a cell.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> A1\ncontent of A1 (a number, a label, or =formula)> =1+\nNot a formula: it has something missing where a number, a cell or ( should be. Nothing was changed.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> A1\ncontent of A1 (a number, a label, or =formula)> =SUM(B1\nNot a formula: it has SUM( with no , between two cells or no ) at the end. Nothing was changed.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> A1\ncontent of A1 (a number, a label, or =formula)> =A1+1\nA1 = #CYCLE; 0 formula cell(s) worked out again.\n1 formula cell(s) are in a cycle, or read one - they show #CYCLE until it is broken.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> A2\ncontent of A2 (a number, a label, or =formula)> =B1/C1\nA2 = #DIV/0; 1 formula cell(s) worked out again.\n1 formula cell(s) are in a cycle, or read one - they show #CYCLE until it is broken.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> A3\ncontent of A3 (a number, a label, or =formula)> label\nA3 = label; 1 formula cell(s) worked out again.\n1 formula cell(s) are in a cycle, or read one - they show #CYCLE until it is broken.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> A4\ncontent of A4 (a number, a label, or =formula)> =A3*2\nA4 = #TEXT; 2 formula cell(s) worked out again.\n1 formula cell(s) are in a cycle, or read one - they show #CYCLE until it is broken.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> A5\ncontent of A5 (a number, a label, or =formula)> =SUM(A3:A4, B9)\nA5 = #TEXT; 3 formula cell(s) worked out again.\n1 formula cell(s) are in a cycle, or read one - they show #CYCLE until it is broken.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> A6\ncontent of A6 (a number, a label, or =formula)> =1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1\nKeep a cell to 60 characters.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> A6\ncontent of A6 (a number, a label, or =formula)> =AVG(B1:B9)\nA6 = #DIV/0; 4 formula cell(s) worked out again.\n1 formula cell(s) are in a cycle, or read one - they show #CYCLE until it is broken.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 2\ncell to empty> A1\nA1 is empty now; 4 formula cell(s) worked out again.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 3\n A B C D E F\n 1\n 2 #DIV/0\n 3 label\n 4 #TEXT\n 5 #TEXT\n 6 #DIV/0\n 7\n 8\n 9\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 4\n A B C D E F\n 1\n 2 =B1/C1\n 3 label\n 4 =A3*2\n 5 =SUM(A3:A~\n 6 =AVG(B1:B~\n 7\n 8\n 9\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 5\nWorked out in this order: A2, A4, A6, A5.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 7\nBye.\n", "interpreter": "equal" }, { "name": "basic", "input": "6\n4\n5\n1\nB3\n1.25\n1\nB7\n=D8/100\n5\n3\n1\nB7\n0.1\n3\n7\n", "screen": "== Mini spreadsheet ==\nCells A1 to F9 hold numbers, labels, or formulas such as =B2*C2 or =SUM(D2:D4).\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 6\nA small order: three items, their totals, tax at 8% and an average.\n A B C D E F\n 1 Item Price Qty Total\n 2 Paper 4.5 3 13.5\n 3 Pens 1.2 10 12\n 4 Folders 2.75 4 11\n 5\n 6 Subtotal 36.5\n 7 Tax rate 0.08 2.92\n 8 Total 39.42\n 9 Average ~12.17\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 4\n A B C D E F\n 1 Item Price Qty Total\n 2 Paper 4.5 3 =B2*C2\n 3 Pens 1.2 10 =B3*C3\n 4 Folders 2.75 4 =B4*C4\n 5\n 6 Subtotal =SUM(D2:D~\n 7 Tax rate 0.08 =D6*B7\n 8 Total =D6+D7\n 9 Average =AVG(D2:D~\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 5\nWorked out in this order: D2, D3, D4, D6, D9, D7, D8.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> B3\ncontent of B3 (a number, a label, or =formula)> 1.25\nB3 = 1.25; 7 formula cell(s) worked out again.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> B7\ncontent of B7 (a number, a label, or =formula)> =D8/100\nB7 = #CYCLE; 5 formula cell(s) worked out again.\n3 formula cell(s) are in a cycle, or read one - they show #CYCLE until it is broken.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 5\nWorked out in this order: D2, D3, D4, D6, D9.\nIn a cycle, or reading one: B7, D7, D8.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 3\n A B C D E F\n 1 Item Price Qty Total\n 2 Paper 4.5 3 13.5\n 3 Pens 1.25 10 12.5\n 4 Folders 2.75 4 11\n 5\n 6 Subtotal 37\n 7 Tax rate #CYCLE #CYCLE\n 8 Total #CYCLE\n 9 Average ~12.33\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 1\ncell> B7\ncontent of B7 (a number, a label, or =formula)> 0.1\nB7 = 0.1; 7 formula cell(s) worked out again.\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 3\n A B C D E F\n 1 Item Price Qty Total\n 2 Paper 4.5 3 13.5\n 3 Pens 1.25 10 12.5\n 4 Folders 2.75 4 11\n 5\n 6 Subtotal 37\n 7 Tax rate 0.1 3.7\n 8 Total 40.7\n 9 Average ~12.33\n\n1) set a cell 2) empty a cell 3) values 4) formulas 5) order 6) sample 7) quit\nchoice> 7\nBye.\n", "interpreter": "equal" } ], "builtOn": [ { "slug": "topological-sort", "caseId": "107-topological-sort", "title": "Topological sort (Kahn's algorithm)" } ], "updated": "2026-10-10" }