The section numbers are per the Berkeley Logo Reference Manual in Brian Harvey's Computer Science Logo Style volume 2: Advanced Techniques for ease of comparison.

1. Data Types
2. Data Structure Primitives
3. Communication
4. Arithmetic
5. Logical Operations
6. Graphics
7. Workspace Management
8. Control Structures

Types

"word

Text string (terminated by whitespace)

:variable

Input definition/variable reference

[ item ... ]

List

( expression )

Parenthesis can be used to group expressions

procedure input ...

Call procedure with default number of inputs

( procedure input ... )

Call procedure with an arbitrary number of inputs

2. Data Structure Primitives

2.1 Constructors

word expr expr

(word expr ...)

Concatenate two (or more) words into one word, separated with spaces

list thing1 thing2

(list thing1 thing2 ...)

Create a new list from the inputs

sentence thing1 thing2

(sentence thing1 thing2 ...)

se thing1 thing2

(se thing1 thing2 ...)

Create a new list from the inputs (if non-lists) or members of the inputs (if lists)

fput thing list

lput thing list

Outputs list, but with thing added as a new first/last item

combine thing1 thing2

If thing2 is a word, like word; otherwise, like fput

reverse list

Outputs a list with the items in reverse order

gensym

Outputs a unique string, e.g. G1, G2, etc.

2.2 Data Selectors

first list

last list

Outputs the first or last item from the list, respectively

butfirst list

bf list

butlast list

bl list

Outputs the list, except for the first/last item

firsts listoflists

Outputs a list of the first item of each sublist

butfirsts listoflists

bfs listoflists

Outputs a list of sublists without the first item

pick list

Outputs one item from a list, at random

item index list

Outputs the indexth item of the list

remove thing list

Outputs the list with any occurences of thing removed

remdup list

Outputs the list with duplicates removed

2.3 Data Mutators

push stackname thing

pop stackname

Push to/pop from a stack i.e. list variable, e.g. make "s [] then push "s 1. Stacks grow from the front.

queue stackname thing

dequeue stackname

Add/remove from a queue i.e. list variable, e.g. make "q [] then queue "q 1. Queues grow from the end

2.4 Predicates

Predicates return 1 (true) or 0 (false)

wordp thing

word? thing

listp thing

list? thing

numberp thing

number? thing

Test if thing is a word, list, or number respectively.

equalp expr expr

equal? expr expr

expr = expr

notequalp expr expr

notequal? expr expr

expr <> expr

Equality/inequality tests. Compares strings, numbers, or lists (equal if length and all members are equal).

emptyp expr

empty? expr

Test if thing is an empty list or empty string.

beforep thing1 thing2

before? thing1 thing2

Test string collation order.

memberp thing list

member? thing list

Test if thing is equal to any member of list.

substringp thing1 thing2

substring? thing1 thing2

Test if thing1 is a substring of thing2.

2.5 Queries

count thing

Outputs length of a list or number of characters in a string

ascii expr

Outputs ASCII (actually, Unicode) code point for first character of string

char expr

Outputs Unicode character at specified code point

uppercase expr

lowercase expr

Outputs string converted to upper/lowercase

3. Communication

3.1 Transmitters

print thing

pr thing

(print thing1 thing2 ...)

(pr thing1 thing2 ...)

Print inputs to the text screen, separated by spaces, and followed by a newline. Square brackets are only put around sublists.

type thing

(type thing1 thing2 ...)

Like print but with no trailing newline.

show thing

(show thing1 thing2 ...)

Like print but with square brackets around list inputs.

3.2 Receivers

readword

(readword promptstr)

Prompt the user for a line of input. The result (including spaces) is the single word output.

3.4 Terminal Access

cleartext

ct

Clear the text screen.

4. Arithmetic

4.1 Numeric Operations

Inputs are numbers or numeric expressions, output is a number.

sum expr expr

(sum expr ...)

expr + expr

difference expr expr

expr - expr

product expr expr

(product expr ...)

expr * expr

quotient expr expr

(quotient expr)

expr / expr

power expr expr

expr ^ expr

Add, subtract, multiply, divide, and raise-to-the-power-of respectively. A single input to quotient returns the reciprocal.

remainder expr expr

expr % expr

modulo expr expr

Outputs the remainder (modulus). For remainder and % the result has the same sign as the first input; for modulo the result has the same sign as a the second input.

minus expr

- expr

Unary minus sign must begin a top-level expression, follow an infix operator, or have a leading space and no trailing space.

abs num

Absolute value

int num

round num

Truncate or round a number, respectively.

sqrt expr

exp expr

log10 expr

ln expr

Square root, e to the power of, common logarithm, and natural logarithm, respectively.

arctan expr

(arctan x y)

sin expr

cos expr

tan expr

The usual trig functions. Angles are in degrees.

radarctan expr

(radarctan x y)

radsin expr

radcos expr

radtan expr

The usual trig functions. Angles are in radians.

iseq first last

Outputs a list with integers from first to last, inclusive

rseq first last count

Outputs a list of count numbers from first to last, inclusive

4.2 Numeric Predicates

greaterp expr expr

greater? expr expr

expr > expr

greaterequalp expr expr

greaterequal? expr expr

expr >= expr

lessp expr expr

less? expr expr

expr <= expr

lessequalp expr expr

lessequal? expr expr

expr <= expr

Greater than, greater than or equal to, less than, less than or equal to, respectively. Inputs are numbers or numeric expressions, output is 1 (true) or 0 (false).

4.3 Random Numbers

random expr

Outputs a random number from 0 through one less than expr

4.5 Bitwise Operations

bitand expr expr

(bitand expr ...)

bitor expr expr

(bitor expr ...)

bitxor expr expr

(bitxor expr ...)

bitnot expr

Bitwise and, or, exclusive-or, and not, respectively.

ashift expr bitcount

Arithmetic bit shift. If bitcount is negative, shifts to the right, preserving sign.

lshift expr bitcount

Logical bit shift. If bitcount is negative, shifts to the right, zero-filling.

5. Logical Operations

true

Outputs 1

false

Outputs 0

and expr expr

(and expr ...)

or expr expr

(or expr ...)

xor expr expr

(xor expr ...)

not expr

Logical "and", "or", "exclusive-or", and "not", respectively. Inputs are numbers or numeric expressions, output is 1 (true) or 0 (false).

6. Graphics

An introduction to Turtle Geometry.

6.1 Turtle Motion

forward expr

fd expr

Move turtle forward expr pixels

back expr

bk expr

Move turtle backward expr pixels

left expr

lt expr

Rotate expr degrees counterclockwise

right expr

rt expr

Rotate expr degrees clockwise

setpos [ expr expr ]

setxy expr expr

setx expr

sety expr

Move turtle to the specified location without drawing

setheading expr

seth expr

Rotate the turtle to the specified heading

home

Moves the turtle to center, pointing upwards

6.2 Turtle Motion Queries

pos

xcor

ycor

Outputs the current turtle position as [ x y ], x or y respectively

heading

Outputs the current turtle heading

towards [ expr expr ]

Outputs the heading towards the specified [ x y ] coordinates

6.3 Turtle and Window Control

showturtle

st

Show the turtle

hideturtle

ht

Hide the turtle

clean

Clear the drawing area

clearscreen

cs

Same as clean and home together

wrap

If the turtle moves off the edge of the screen it will continue on the other side. (default)

window

The turtle can move past the edges of the screen, unbounded.

fence

The turtle attempts to move past the edge of the screen it will stop.

label expr

Draw a word (same logic as print) on the graphics display at the turtle location

setlabelheight expr

Set the height for text drawn by label, in pixels

6.4 Turtle and Window Queries

shownp

shown?

Outputs 1 if the turtle is shown, 0 if the turtle is hidden

turtlemode

Outputs WRAP, WINDOW or FENCE

labelsize

Outputs the height of text drawn by label, in pixels

6.5 Pen and Background Control

pendown

pd

Turtle resumes leaving a trail

penup

pu

Turtle stops leaving a trail

penpaint

penerase

penreverse

Change the turtle drawing mode - paint (the default) leaves a colored trail, erase restores the background, reverse inverts the background.

setpencolor logocolor

setpencolor csscolor

(setpencolor expr expr expr)

Set pen/text color. Color can be a standard Logo color number (0-15), CSS color string (CSS color names or #rrggbb), or in the 3-input version, r/g/b values in 0...99.

The standard Logo colors are:

0: black	1: blue	2: green	3: cyan
4: red	5: magenta	6: yellow	7: white
8: brown	9: tan	10: green	11: aqua
12: salmon	13: purple	14: orange	15: gray

setpensize expr

Set pen width in pixels. If expr is a list, the first member is used.

6.6 Pen Queries

pendownp

pendown?

Outputs 1 if the pen is down, 0 otherwise

penmode

Outputs PAINT, ERASE or REVERSE

pencolor

Outputs the current pen color. This will be a CSS color string, not necessarily the value passed in.

pensize

Outputs a two element list with the pen width and height (usually the same).

7. Workspace Management

7.1 Procedure Definition

to procname inputs ... statements ... end

Define a new named procedure with optional inputs

def procname

Outputs the definition of a named procedure as a string

7.2 Variable Definition

make varname expr

Update a variable or define a new global variable. The variable name must be quoted, e.g. make "foo 5

name expr varname

Like make but with the inputs reversed

local varname

(local varname ...)

A subsequent make will create the variable(s) in the local scope instead of the global scope

localmake varname expr

Define a variable in the local scope (shortcut for local then make

thing varname

Outputs the value of variable. :foo is a shortcut for thing "foo

global varname

Reserve the variable at the global scope. This doesn't do anything useful.

7.4 Workspace Predicates

Predicates return 1 (true) or 0 (false)

procedurep name

procedure? name

Test if there is a procedure with the given name.

primitivep name

primitive? name

Test if there is a built-in procedure with the given name.

definedp name

defined? name

Test if there is a user-defined procedure with the given name.

namep name

name? name

Test if there is a variable with the given name.

7.5 Workspace Queries

contents

Outputs a list with two members. The first is a list of user-defined procedure names. The second is a list of defined variables.

procedures

Outputs a list of user-defined procedure names.

primitives

Outputs a list of primitive procedure names.

globals

Outputs a list of defined global variables.

names

Outputs a list with two members. The first is an empty list. The second is a list of defined variables.

7.7 Workspace Control

erase contentslist

Takes a two member list, where the first is a list of user-defined procedure names to erase, and the second is a list of defined variables to erase.

erall

Erase all user-defined procedures and variables.

8. Control Structures

8.1 Control

run [ statements ... ]

Run the specified statements once

runresult [ statements ... ]

Run the specified statements once. If the statements return a value, the result is a list with the value as a single member. Otherwise, the result is an empty list.

repeat expr [ statements ... ]

Repeat statements expr times

forever [ statements ... ]

Repeat statements forever. Used inside a user-defined procedure that terminates with output or stop

repcount

Outputs the current iteration number of the current repeat or forever

if expr [ statements ... ]

Execute statements if the expression is non-zero

ifelse expr [ statements ... ] [ statements ... ]

Execute first set of statements if the expression is non-zero, otherwise execute the second set

test expr

Test the specified expression, save the result in the local scope for subsequent use by iftrue or iffalse

iftrue [ statements ...]

ift [ statements ...]

iffalse [ statements ...]

iff [ statements ...]

Run the statements if the result of the last local test was non-zero (true) or zero (false) respectively.

stop

End the running procedure with no output value

output expr

op expr

End the running procedure and output the specified value

bye

Terminate the program

.maybeoutput expr

Like output if expr returns a value, like stop otherwise

ignore expr

Evaluate and ignore results of the expression

for controllist [ statements ...]

Typical for loop. The controllist specifies three or four members: the local varname, start value, limit value, and optional step size.

do.while [ statements ...] expr

Runs the specified statements at least once, and repeats while the expression is non-zero (true).

while expr [ statements ...]

Runs the specified statements only while the expression remains non-zero (true).

do.until[ statements ...] expr

Runs the specified statements at least once, and repeats while the expression is zero (false).

until expr [ statements ...]

Runs the specified statements only while the expression remains zero (false).

8.2 Template-based Iteration

These higher-level procedures support only the "named procedure" form of template. The first input is the name of a procedure to call.

apply procname list

Call procname with the members of list as inputs

invoke procname input1

(invoke procname input1 ...)

Call procname with the specified inputs as inputs

foreach procname list

call procname for each item in the list

map procname list

Outputs a list composed of the results of calling procname for each item in the list

filter procname list

Outputs a list composed of the input list where procname called on the item returns non-zero (true)

find procname list

Outputs the first item in list for which calling procname on it returns non-zero (true). If not found, the empty list is returned.

reduce procname list

(reduce procname list initial)

Call procname repeatedly with two inputs - the current value and the next list item. If initial is not specified, the first list element is used instead.