Pretty Print Table Data in Common Lisp

CL-PrettyPrintTableData.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Pretty Printing Table Data in Common Lisp\n",
    "\n",
    "Common Lisp has a powerfull but _byzantine_ string formatting language which can do all sorts\n",
    "of magic. Here we are using the power of\n",
    "[format](http://www.lispworks.com/documentation/HyperSpec/Body/22_c.htm)\n",
    "to produce [ASCII art](https://en.wikipedia.org/wiki/ASCII_art)\n",
    "tables from tabular data."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Objective\n",
    "\n",
    "Table output should:\n",
    "* be general purpose (i.e. not specialized to numbers)\n",
    "* be _pretty_ in its ASCII form\n",
    "* support simple column level text alignment\n",
    "* should be usable in Markdown text."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## About this Jupyter Notebook\n",
    "\n",
    "This _Gist_ was created using:\n",
    "* the [Jupyter Lab](https://jupyter.org/) computational notebook.\n",
    "* the [common-lisp-jupyter](https://yitzchak.github.io/common-lisp-jupyter/) kernel by Frederic Peschanski.\n",
    "* [Steel Bank Common Lisp](http://www.sbcl.org/) (SBCL)."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Coding Style\n",
    "\n",
    "For the most part the [Google Common Lisp Style Guide](https://google.github.io/styleguide/lispguide.xml) is used."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Table Formatting\n",
    "\n",
    "The format of choice for table output format is [Markdown](https://www.markdownguide.org/getting-started)\n",
    "_[pipe tables](https://www.markdownguide.org/extended-syntax)_ which:\n",
    "* Provides basic cell alignment instructions (left, right, center)\n",
    "* Is pretty in ASCII form.\n",
    "\n",
    "**Example:**\n",
    "\n",
    "The Markdown pipe table:\n",
    "\n",
    "~~~\n",
    "| Coord  | Value |\n",
    "| :----: | ----: |\n",
    "|      X | 12.5  |\n",
    "|      Y |  3.1  |\n",
    "|      Z | 19.0  |\n",
    "~~~\n",
    "\n",
    "Renders as (Note: At the time of writing GitHub flavored Markdown did not support column alignment):\n",
    "\n",
    "| Coord  | Value |\n",
    "| :----: | ----: |\n",
    "|      X | 12.5  |\n",
    "|      Y |  3.1  |\n",
    "|      Z | 19.0  |\n",
    "\n",
    "\n",
    "We want to do the heavy lifting of formatting key-value data only once, therefore we first define a generic table data model which can be easily generated from a variety of data structures.\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Table Cell Formatting\n",
    "\n",
    "To properly format table cells we need to find the corresponding formatting instructions using:\n",
    "* [Tilde Less-Than-Sign: Justification](http://www.lispworks.com/documentation/HyperSpec/Body/22_cfb.htm)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\"|Test      |\""
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    },
    {
     "data": {
      "text/plain": [
       "\"|   Test   |\""
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    },
    {
     "data": {
      "text/plain": [
       "\"|      Test|\""
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(format nil \"|~vA|\"       10 \"Test\") ; Left align text in a table cell\n",
    "(format nil \"|~v:@<~A~>|\" 10 \"Test\") ; Center text in a table\n",
    "(format nil \"|~v@A|\"      10 \"Test\") ; Right align text in a table cell"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Table Data Model \n",
    "\n",
    "To represent table date we use a simple and intuitive list-of-lists model which looks like:\n",
    "\n",
    "~~~ Lisp\n",
    " '(( <obj1.1> ... <obj1.N>)  ; row 1\n",
    "   ...\n",
    "   ( <objN.1> ... <objN.N>)) ; row N\n",
    "~~~"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Table Cell Alignment Format Specification\n",
    "\n",
    "With the preparation from the previous chapter the format function can now be implemented.\n",
    "We start with defining a property list which maps alignment keywords to cell format strings."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "+CELL-FORMATS+"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(defconstant +CELL-FORMATS+ '(:left   \"~vA\"\n",
    "                              :center \"~v:@<~A~>\"\n",
    "                              :right  \"~v@A\"))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## format-table [Function]\n",
    "\n",
    "Format table data as Markdown pipe table:\n",
    "\n",
    "~~~ Lisp\n",
    "(format-table stream data [:column-label {string list}]\n",
    "                          [:colun-align  {keyword list}])\n",
    "~~~\n",
    "\n",
    "#### Arguments\n",
    "\n",
    "stream {`output-stream`}\n",
    "> The stream to write the table to. The symbol `T` can be used as\n",
    "> an alias for `*standard-output*`\n",
    "\n",
    "data {`list of lists`}\n",
    "> Table data of the form:\n",
    ">\n",
    "> ~~~ Lisp\n",
    "> '((<obj1.1> ... <obj1.N>)  ; row 1\n",
    ">       ...\n",
    ">   (<objN.1> ... <objN.N>)) ; row N\n",
    "> ~~~\n",
    "\n",
    "column-label {`string list`} default `'(\"COL1\" ... \"COLn\")`\n",
    "> Optional list of column labels. If omitted the default labels\n",
    "> `\"COL1\" ... \"COLn\"` are used. The\n",
    "> length of the colum header list given in this parameter must be\n",
    "> identical to the number of columns in the table.\n",
    "\n",
    "column-align {`keyword list`} default `'(:left ... :left)}`\n",
    "> Optional list of column alignments. A column alignment is\n",
    "> one of the keywords `:left`, `:center`, `:right`. The\n",
    "> length of the keyword list given in this parameter must be\n",
    "> identical to the number of columns in the table."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "FORMAT-TABLE"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(defun format-table (stream data &key (column-label (loop for i from 1 to (length (car data))\n",
    "                                                          collect (format nil \"COL~D\" i)))\n",
    "                                      (column-align (loop for i from 1 to (length (car data))\n",
    "                                                          collect :left)))\n",
    "    (let* ((col-count (length column-label))\n",
    "           (strtable  (cons column-label ; table header\n",
    "                          (loop for row in data ; table body with all cells as strings\n",
    "                              collect (loop for cell in row\n",
    "                                           collect (if (stringp cell)\n",
    "                                                        cell\n",
    "                                                    ;else\n",
    "                                                        (format nil \"~A\" cell))))))\n",
    "           (col-widths (loop with widths = (make-array col-count :initial-element 0)\n",
    "                           for row in strtable\n",
    "                           do (loop for cell in row\n",
    "                                    for i from 0\n",
    "                                  do (setf (aref widths i)\n",
    "                                         (max (aref widths i) (length cell))))\n",
    "                           finally (return widths))))\n",
    "        ;------------------------------------------------------------------------------------\n",
    "        ; splice in the header separator\n",
    "        (setq strtable\n",
    "              (nconc (list (car strtable) ; table header\n",
    "                           (loop for align in column-align ; generate separator\n",
    "                                 for width across col-widths\n",
    "                               collect (case align\n",
    "                                           (:left   (format nil \":~v@{~A~:*~}\"\n",
    "                                                        (1- width)  \"-\"))\n",
    "                                           (:right  (format nil \"~v@{~A~:*~}:\"\n",
    "                                                        (1- width)  \"-\"))\n",
    "                                           (:center (format nil \":~v@{~A~:*~}:\"\n",
    "                                                        (- width 2) \"-\")))))\n",
    "                           (cdr strtable))) ; table body\n",
    "        ;------------------------------------------------------------------------------------\n",
    "        ; Generate the formatted table\n",
    "        (let ((row-fmt (format nil \"| ~{~A~^ | ~} |~~%\" ; compile the row format\n",
    "                           (loop for align in column-align\n",
    "                               collect (getf +CELL-FORMATS+ align))))\n",
    "              (widths  (loop for w across col-widths collect w)))\n",
    "            ; write each line to the given stream\n",
    "            (dolist (row strtable)\n",
    "                (apply #'format stream row-fmt (mapcan #'list widths row)))))\n",
    ")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "toc-hr-collapsed": false
   },
   "source": [
    "# Examples\n",
    "\n",
    "The table data sets used in the examples below were shamelessly stolen from the\n",
    "[Northwind Database](https://github.com/graphql-compose/graphql-compose-examples/tree/master/examples/northwind/data/csv)."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Customer Table"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "+CUSTOMER-DATA+"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(defconstant +CUSTOMER-DATA+\n",
    "  '((:ALFKI\t\"Alfreds Futterkiste\" \"Maria Anders\")\n",
    "    (:ANATR\t\"Ana Trujillo Emparedados y helados\" \"Ana Trujillo\")\n",
    "    (:ANTON\t\"Antonio Moreno Taquería\" \"Antonio Moreno\")\n",
    "    (:AROUT\t\"Around the Horn\" \"Thomas Hardy\")\n",
    "    (:BERGS\t\"Berglunds snabbköp\" \"Christina Berglund\")\n",
    "    (:BLAUS\t\"Blauer See Delikatessen\" \"Hanna Moos\")\n",
    "    (:BLONP\t\"Blondesddsl père et fils\" \"Frédérique Citeaux\")\n",
    "    (:BOLID\t\"Bólido Comidas preparadas\" \"Martín Sommer\")\n",
    "    (:BONAP\t\"Bon app'\" \"Laurence Lebihan\")\n",
    "    (:BOTTM\t\"Bottom-Dollar Markets\" \"Elizabeth Lincoln\")\n",
    "    (:BSBEV\t\"B's Beverages\" \"Victoria Ashworth\")\n",
    "    (:CACTU\t\"Cactus Comidas para llevar\" \"Patricio Simpson\")\n",
    "    (:CENTC\t\"Centro comercial Moctezuma\" \"Francisco Chang\")\n",
    "    (:CHOPS\t\"Chop-suey Chinese\" \"Yang Wang\")\n",
    "    (:COMMI\t\"Comércio Mineiro\" \"Pedro Afonso\")\n",
    "    (:CONSH\t\"Consolidated Holdings\" \"Elizabeth Brown\")\n",
    "    (:DRACD\t\"Drachenblut Delikatessen\" \"Sven Ottlieb\")))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "NIL"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "|    ID |                           Customer |      Contact       |\n",
      "| ----: | ---------------------------------: | :----------------: |\n",
      "| ALFKI |                Alfreds Futterkiste |    Maria Anders    |\n",
      "| ANATR | Ana Trujillo Emparedados y helados |    Ana Trujillo    |\n",
      "| ANTON |            Antonio Moreno Taquería |   Antonio Moreno   |\n",
      "| AROUT |                    Around the Horn |    Thomas Hardy    |\n",
      "| BERGS |                 Berglunds snabbköp | Christina Berglund |\n",
      "| BLAUS |            Blauer See Delikatessen |     Hanna Moos     |\n",
      "| BLONP |           Blondesddsl père et fils | Frédérique Citeaux |\n",
      "| BOLID |          Bólido Comidas preparadas |   Martín Sommer    |\n",
      "| BONAP |                           Bon app' |  Laurence Lebihan  |\n",
      "| BOTTM |              Bottom-Dollar Markets | Elizabeth Lincoln  |\n",
      "| BSBEV |                      B's Beverages | Victoria Ashworth  |\n",
      "| CACTU |         Cactus Comidas para llevar |  Patricio Simpson  |\n",
      "| CENTC |         Centro comercial Moctezuma |  Francisco Chang   |\n",
      "| CHOPS |                  Chop-suey Chinese |     Yang Wang      |\n",
      "| COMMI |                   Comércio Mineiro |    Pedro Afonso    |\n",
      "| CONSH |              Consolidated Holdings |  Elizabeth Brown   |\n",
      "| DRACD |           Drachenblut Delikatessen |    Sven Ottlieb    |\n",
      "\n",
      "Evaluation took:\n",
      "  0.000 seconds of real time\n",
      "  0.000000 seconds of total run time (0.000000 user, 0.000000 system)\n",
      "  100.00% CPU\n",
      "  1,054,994 processor cycles\n",
      "  65,456 bytes consed\n",
      "  \n"
     ]
    }
   ],
   "source": [
    "; DEMO: Create a formatted table from data with 3 columns\n",
    "(time (format-table t +CUSTOMER-DATA+\n",
    "                    :column-label '(\"ID\" \"Customer\" \"Contact\")\n",
    "                    :column-align '(:right :right :center)))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "When rendered with a Markdown viewer the table looks like (Note: At the time of writing GitHub flavored Markdown did not support column alignment): \n",
    "\n",
    "   ID |                           Customer |      Contact      \n",
    "----: | ---------------------------------: | :----------------:\n",
    "ALFKI |                Alfreds Futterkiste |    Maria Anders   \n",
    "ANATR | Ana Trujillo Emparedados y helados |    Ana Trujillo   \n",
    "ANTON |            Antonio Moreno Taquería |   Antonio Moreno  \n",
    "AROUT |                    Around the Horn |    Thomas Hardy   \n",
    "BERGS |                 Berglunds snabbköp | Christina Berglund\n",
    "BLAUS |            Blauer See Delikatessen |     Hanna Moos    \n",
    "BLONP |           Blondesddsl père et fils | Frédérique Citeaux\n",
    "BOLID |          Bólido Comidas preparadas |   Martín Sommer   \n",
    "BONAP |                           Bon app' |  Laurence Lebihan \n",
    "BOTTM |              Bottom-Dollar Markets | Elizabeth Lincoln \n",
    "BSBEV |                      B's Beverages | Victoria Ashworth \n",
    "CACTU |         Cactus Comidas para llevar |  Patricio Simpson \n",
    "CENTC |         Centro comercial Moctezuma |  Francisco Chang  \n",
    "CHOPS |                  Chop-suey Chinese |     Yang Wang     \n",
    "COMMI |                   Comércio Mineiro |    Pedro Afonso   \n",
    "CONSH |              Consolidated Holdings |  Elizabeth Brown  \n",
    "DRACD |           Drachenblut Delikatessen |    Sven Ottlieb   "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Single Column Data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "+SINGLE-COLUMN-DATA+"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(defconstant +SINGLE-COLUMN-DATA+\n",
    "  '((\"Alfreds Futterkiste\")\n",
    "    (\"Ana Trujillo Emparedados y helados\")\n",
    "    (\"Antonio Moreno Taquería\")\n",
    "    (\"Around the Horn\")\n",
    "    (\"Berglunds snabbköp\")\n",
    "    (\"Blauer See Delikatessen\")\n",
    "    (\"Blondesddsl père et fils\")\n",
    "    (\"Bólido Comidas preparadas\")\n",
    "    (\"Bon app'\")\n",
    "    (\"Bottom-Dollar Markets\")\n",
    "    (\"B's Beverages\")\n",
    "    (\"Cactus Comidas para llevar\")\n",
    "    (\"Centro comercial Msoctezuma\")\n",
    "    (\"Chop-suey Chinese\")\n",
    "    (\"Comércio Mineiro\")\n",
    "    (\"Consolidated Holdings\")\n",
    "    (\"Drachenblut Delikatessen\")))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "NIL"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "|              Customer              |\n",
      "| :--------------------------------: |\n",
      "|        Alfreds Futterkiste         |\n",
      "| Ana Trujillo Emparedados y helados |\n",
      "|      Antonio Moreno Taquería       |\n",
      "|          Around the Horn           |\n",
      "|         Berglunds snabbköp         |\n",
      "|      Blauer See Delikatessen       |\n",
      "|      Blondesddsl père et fils      |\n",
      "|     Bólido Comidas preparadas      |\n",
      "|              Bon app'              |\n",
      "|       Bottom-Dollar Markets        |\n",
      "|           B's Beverages            |\n",
      "|     Cactus Comidas para llevar     |\n",
      "|    Centro comercial Msoctezuma     |\n",
      "|         Chop-suey Chinese          |\n",
      "|          Comércio Mineiro          |\n",
      "|       Consolidated Holdings        |\n",
      "|      Drachenblut Delikatessen      |\n",
      "\n",
      "Evaluation took:\n",
      "  0.000 seconds of real time\n",
      "  0.000000 seconds of total run time (0.000000 user, 0.000000 system)\n",
      "  100.00% CPU\n",
      "  320,908 processor cycles\n",
      "  0 bytes consed\n",
      "  \n"
     ]
    }
   ],
   "source": [
    "; DEMO: Create a formatted table from data with 1 column\n",
    "(time (format-table t +SINGLE-COLUMN-DATA+\n",
    "                    :column-label '(\"Customer\")\n",
    "                    :column-align '(:center)))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Tables with Numbers"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "+NUMERIC-DATA+"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(defconstant +NUMERIC-DATA+\n",
    "    '((10248 11  14.00 12 0)\n",
    "       (10248 42  9.80 10 0)\n",
    "       (10248 72 34.80  5 0)\n",
    "       (10249 14 18.60  9 0)\n",
    "       (10249 51 42.40 40 0)\n",
    "       (10250 41  7.70 10 0)\n",
    "       (10250 51 42.40 35 0.15)\n",
    "       (10250 65 16.80 15 0.15)\n",
    "       (10251 22 16.80  6 0.05)\n",
    "       (10251 57 15.60 15 0.05)\n",
    "       (10251 65 16.80 20 0)))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "NIL"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "| Order# | Product# | Price | Quantity | Discount |\n",
      "| :----: | :------: | ----: | -------: | :------- |\n",
      "| 10248  |    11    |  14.0 |       12 | 0        |\n",
      "| 10248  |    42    |   9.8 |       10 | 0        |\n",
      "| 10248  |    72    |  34.8 |        5 | 0        |\n",
      "| 10249  |    14    |  18.6 |        9 | 0        |\n",
      "| 10249  |    51    |  42.4 |       40 | 0        |\n",
      "| 10250  |    41    |   7.7 |       10 | 0        |\n",
      "| 10250  |    51    |  42.4 |       35 | 0.15     |\n",
      "| 10250  |    65    |  16.8 |       15 | 0.15     |\n",
      "| 10251  |    22    |  16.8 |        6 | 0.05     |\n",
      "| 10251  |    57    |  15.6 |       15 | 0.05     |\n",
      "| 10251  |    65    |  16.8 |       20 | 0        |\n",
      "\n",
      "Evaluation took:\n",
      "  0.000 seconds of real time\n",
      "  0.000000 seconds of total run time (0.000000 user, 0.000000 system)\n",
      "  100.00% CPU\n",
      "  666,304 processor cycles\n",
      "  65,376 bytes consed\n",
      "  \n"
     ]
    }
   ],
   "source": [
    "; DEMO: Create a formatted table from data with 3 columns\n",
    "(time (format-table t +NUMERIC-DATA+\n",
    "                    :column-label '(\"Order#\" \"Product#\" \"Price\" \"Quantity\" \"Discount\")\n",
    "                    :column-align '(:center :center :right :right :left)))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Reference"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Formatting Directives\n",
    "\n",
    "These format commands were used in the implementation of the pretty print methods:\n",
    "\n",
    "* [Tilde Tilde](http://www.lispworks.com/documentation/HyperSpec/Body/22_cae.htm)\n",
    "* [Tilde Left-Brace: Iteration](http://www.lispworks.com/documentation/HyperSpec/Body/22_cgd.htm)\n",
    "* [Tilde Asterisk: Go-To](http://www.lispworks.com/documentation/HyperSpec/Body/22_cga.htm)\n",
    "* [Tilde Less-Than-Sign: Justification](http://www.lispworks.com/documentation/HyperSpec/Body/22_cfb.htm)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## See also\n",
    "* [18. A Few FORMAT Recipes](http://www.gigamonkeys.com/book/a-few-format-recipes.html) from  [Practical Common Lisp](http://www.gigamonkeys.com/book/)\n",
    "* [22.3 Formatted Output](http://www.lispworks.com/documentation/HyperSpec/Body/22_c.htm) from [Common Lisp Hyperspec](http://www.lispworks.com/documentation/HyperSpec/Front/index.htm)\n",
    "* [Google Common Lisp Style Guide](https://google.github.io/styleguide/lispguide.xml)\n",
    "* [pipe tables](https://www.markdownguide.org/extended-syntax) from [Markdown Guide](https://www.markdownguide.org)\n",
    "* [What is Markdown](https://www.markdownguide.org/getting-started) from [Markdown Guide](https://www.markdownguide.org)\n",
    "* [A simple data dump from SQL's Northwind database to CSV](https://github.com/graphql-compose/graphql-compose-examples/tree/master/examples/northwind/data/csv)"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Common Lisp",
   "language": "common-lisp",
   "name": "common-lisp"
  },
  "language_info": {
   "codemirror_mode": "text/x-common-lisp",
   "file_extension": ".lisp",
   "mimetype": "text/x-common-lisp",
   "name": "common-lisp",
   "pygments_lexer": "common-lisp",
   "version": "2.0.0"
  },
  "toc": {
   "base_numbering": 1,
   "nav_menu": {},
   "number_sections": true,
   "sideBar": true,
   "skip_h1_title": false,
   "title_cell": "Table of Contents",
   "title_sidebar": "Contents",
   "toc_cell": true,
   "toc_position": {
    "height": "calc(100% - 180px)",
    "left": "10px",
    "top": "150px",
    "width": "193.865px"
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 "nbformat": 4,
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}

You can get rid of APPLY:

CL-USER 70 > (apply #'nconc (mapcar (lambda (w s) (list w s)) '(1 2 3 4) '(a b c d)))
(1 A 2 B 3 C 4 D)

CL-USER 71 > (apply #'nconc (mapcar #'list '(1 2 3 4) '(a b c d)))
(1 A 2 B 3 C 4 D)

CL-USER 72 > (mapcan #'list '(1 2 3 4) '(a b c d))
(1 A 2 B 3 C 4 D)

Very good catch lispm! Your input is very much appreciated!

This is great. I am about finished with table formatting functions for use with the pretty printer and thought about a markdown/restructured text version. Glad I found this. Perhaps these two could be combined into a project, say, "formatted-tables" ? My stuff is under the MS-PL. What's the license for this?

@Symbolics, the code has no usage restrictions. Use it as you see fit.