Update docs

prelude.md

@@ -12,6 +12,24 @@ or they are variations on a function, e.g. `div/0` as a variation on `div`.
 
 **How entries are formatted.** Each entry has a brief (sometimes too brief!) description of what it does.
 It is followed by the patterns for each of its function clauses.
+This should be enough to indicate order of arguments, types, and so on.
+
+**Patterns often, but do not always, indicate types.** Typed patterns are written as `foo as :bar`,
+where the type is indicated by the keyword. 
+Possible ludus types are: `:nil`, `:boolean`, `:number`, `:keyword` (atomic values);
+`:string` (strings are their own beast); `:tuple` and `:list` (indexed collections); `:set` (sets are specific), 
+`:dict` and `:ns` (associative collections); and `:ref` (references).
+
+**Conventional types.** Ludus has two types based on conventions.
+* _Result tuples._ Results are a way of modeling the result of a calculation that might fail.
+The two possible values are `(:ok, value)` and `(:err, msg)`.
+`msg` is usually a string describing what went wrong.
+To work with result tuples, see [`unwrap!`](#unwrap) and [`unwrap_or`](#unwrap_or).
+That said, usually you work with these using pattern matching.
+
+* _Vectors._ Vectors are 2-element tuples of x and y coordinates.
+The origin is `(0, 0)`. 
+`add` and `mult` can take vectors as well as numbers.
 
 [abs](#abs)    [add](#add)    [and](#and)    [angle](#angle)    [append](#append)    [assert!](#assert)    [assoc](#assoc)    [assoc?](#assoc)    [at](#at)    [atan/2](#atan/2)    [back!](#back)    [background!](#background)    [bg!](#bg)    [bgcolor](#bgcolor)    [bk!](#bk)    [bool](#bool)    [bool?](#bool)    [butlast](#butlast)    [ceil](#ceil)    [clear!](#clear)    [coll?](#coll)    [colors](#colors)    [concat](#concat)    [console](#console)    [cos](#cos)    [count](#count)    [dec](#dec)    [deg/rad](#deg/rad)    [deg/turn](#deg/turn)    [deref](#deref)    [dict](#dict)    [diff](#diff)    [dissoc](#dissoc)    [dist](#dist)    [div](#div)    [div/0](#div/0)    [div/safe](#div/safe)    [doc!](#doc)    [each!](#each)    [eq?](#eq)    [err](#err)    [err?](#err)    [even?](#even)    [false?](#false)    [fd!](#fd)    [first](#first)    [floor](#floor)    [flush!](#flush)    [fn?](#fn)    [fold](#fold)    [forward!](#forward)    [get](#get)    [goto!](#goto)    [gt?](#gt)    [gte?](#gte)    [heading](#heading)    [heading/vector](#heading/vector)    [home!](#home)    [inc](#inc)    [join](#join)    [keys](#keys)    [keyword?](#keyword)    [last](#last)    [left!](#left)    [list](#list)    [lt!](#lt)    [lt?](#lt)    [lte?](#lte)    [make!](#make)    [map](#map)    [mod](#mod)    [mult](#mult)    [neg](#neg)    [neg?](#neg)    [nil?](#nil)    [not](#not)    [odd?](#odd)    [ok](#ok)    [ok?](#ok)    [or](#or)    [ordered?](#ordered)    [p5_calls](#p5_calls)    [panic!](#panic)    [pc!](#pc)    [pd!](#pd)    [pencolor](#pencolor)    [pencolor!](#pencolor)    [pendown!](#pendown)    [pendown?](#pendown)    [penup!](#penup)    [penwidth](#penwidth)    [penwidth!](#penwidth)    [pi](#pi)    [pos?](#pos)    [position](#position)    [print!](#print)    [prn!](#prn)    [pu!](#pu)    [pw!](#pw)    [rad/deg](#rad/deg)    [rad/turn](#rad/turn)    [random](#random)    [range](#range)    [render_turtle!](#render_turtle)    [report!](#report)    [reset_turtle!](#reset_turtle)    [rest](#rest)    [right!](#right)    [round](#round)    [rt!](#rt)    [second](#second)    [set](#set)    [show](#show)    [sin](#sin)    [slice](#slice)    [some](#some)    [some?](#some)    [square](#square)    [string](#string)    [string?](#string)    [sub](#sub)    [sum_of_squares](#sum_of_squares)    [tan](#tan)    [tau](#tau)    [turn/deg](#turn/deg)    [turn/rad](#turn/rad)    [turtle_commands](#turtle_commands)    [turtle_state](#turtle_state)    [turtle_states](#turtle_states)    [type](#type)    [unwrap!](#unwrap)    [unwrap_or](#unwrap_or)    [update](#update)    [update!](#update)    [values](#values)    [zero?](#zero)
 ## Function documentation

target/repl-port

@@ -1 +0,0 @@
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