# This is a single line comment in LDPL.
# LDPL doesn't have multi-line comments.

# LDPL is a case-insensitive language: dIsPlaY and DISPLAY are the same
# statement, and foo and FOO name the same variable.

# An LDPL source file is divided in two sections, the DATA section and
# the PROCEDURE section.

DATA:
# Within the DATA section, variables are declared.

myNumber is number          # Defines a real number.
myString is text            # Defines a string.
myList is number list       # Defines a list of numbers.
myMap  is number map        # Defines a map of numbers.

# LDPL understands four data types: two scalar types (NUMBER, TEXT)
# and two container types (LISTs and MAPs).
# LISTs can be TEXT LISTs or NUMBER LISTs, while MAPs can be
# TEXT MAPs and NUMBER MAPs. You can also chain many containers
# to create larger data types:
textListList is text list list
myMulticontainer is number list list map 
# Defines a map of lists of lists of numbers.

PROCEDURE:
# Within the PROCEDURE section, your code is written.

store -19.2 in myNumber         # Use the STORE statement to assign values
store "Hi there" in myString    # to variables.
push 890 to myList # Use PUSH - TO to append values to lists.
push 100 to myList
push 500 to myList
store 45 in myMap:"someIndex" # Use the : operator to index containers.

push list to textListList # Push an empty list into a list of lists.
push "LDPL is nice!" to textListList:0 #Push text to the pushed list.

display "Hello World!" # Use the DISPLAY statement to print values.
# The display statement can receive multiple values separated by spaces.
display crlf "How are you today?" myNumber myString crlf
# CRLF is the standard line break value in LDPL.
display textListList:0:0 " Isn't it?" crlf

# IF statements in LDPL are extremely verbose:
if myNumber is equal to -19.2 and myList:0 is less than 900 then
    display "Yes!" crlf
else if myMap:"someIndex" is not equal to 45 then
    display "This is an else if!" crlf
else
    display "Else!" crlf
end if
# Valid LDPL comparison operators are
# - IS EQUAL TO
# - IS NOT EQUAL TO
# - IS LESS THAN
# - IS GREATER THAN
# - IS LESS THAN OR EQUAL TO
# - IS GREATER THAN OR EQUAL TO
if "Hi there!" is not equal to "Bye bye!" then
    display "Yep, those weren't equal." crlf
end if
# LDPL normally doesn't understand inline expressions, so you
# cannot do stuff like:
# if myNumber - 9 * 2 is equal to 10 then
# LDPL will set your computer on fire and burst your screen if you do so.

# WHILE loops follow the same rules
store 0 in myNumber
while myNumber is less than 10 do
    display "Loop number " myNumber "..." crlf
    in myNumber solve myNumber + 1 # You can do math like this.
repeat
# You can use 'break' and 'continue' inside loops just like any other language.

# LDPL also has FOR loops and FOR EACH loops
for myNumber from 0 to 100 step 2 do
    display myNumber crlf
repeat

for each myNumber in myList do
    display myNumber
repeat

display "Enter your name: "
accept myString # Use ACCEPT to let the user input values.
display "Hi there, " myString crlf
display "How old are you?: "
accept myNumber
if myNumber is greater than 200 then
    display "Woah, you are so old!" crlf
end if

wait 1000 milliseconds # Pause the program for a whole second.

# Let's do some math
store 1.2 in myNumber
in myNumber solve myNumber * (10 / 7.2) # Operators are separated by spaces.
floor myNumber
display myNumber crlf
get random in myNumber # get a random number between 0 and 1 
                       # and store it in myNumber

# Functions in LDPL are called sub-procedures. Sub-procedures, like source
# files, are divided in sections. The sections found in sub-procedures are
# the PARAMETERS section, the LOCAL DATA section and the PROCEDURE section.
# All sections except the PROCEDURE section can be skipped if they aren't
# used. If no PARAMETERS nor LOCAL DATA sections are used, the PROCEDURE
# keyword may be omitted.
sub myFunction
    parameters:
        a is number # LDPL is pass by reference
        b is number
        result is number # Thus you can return values through a parameter.
    local data:
        c is number
    procedure:
        get random in c
        in result solve a + b * c
end sub

sub sayHello
    display "Hi there!" crlf
    return
    display "This won't be displayed :("
end sub

call myFunction with 1 2 myNumber
display myNumber crlf
call sayHello
call sayBye # sub-procedures may be called before they are declared

sub sayBye
    display "Bye!"
end sub

# One of the greatest features of LDPL is the ability to create your
# own statements.

create statement "say hi" executing sayHello
say hi

create statement "random add $ and $ in $" executing myFunction
random add 1 and 2 in myNumber
display myNumber crlf

exit