Basic Syntax

Droe's syntax is designed to be readable and expressive, using natural language constructs that make code easy to understand and maintain.

Comments

Droe supports both single-line and multi-line comments:

// This is a single-line comment

/* This is a
   multi-line comment
   that spans several lines */

display "Hello, World!"  // Inline comment

Comments are ignored by the compiler and are used to document your code.

Display Statements

The most basic operation in Droe is displaying output:

display "Hello, World!"
display ""                    // Empty line
display "Welcome to Droe"

You can display variables and expressions:

set name which is text to "Alice"
display name
display "Hello, " + name      // String concatenation
display "Name: [name]"        // String interpolation

Keywords and Identifiers

Reserved Keywords

Droe uses natural language keywords:

// Variable declaration
set name which is text to "value"

// Conditionals  
when condition then
  // code
end when

// Loops
for each item in collection
  // code
end for

// Modules and actions
module name
  action name with params gives type
    give result
  end action
end module

Identifiers

Variable and module names follow these rules:

• Must start with a letter (a-z, A-Z)
• Can contain letters, numbers, and underscores
• Case-sensitive
• Cannot be reserved keywords

// Valid identifiers
set user_name which is text to "Alice"
set firstName which is text to "Bob"
set counter1 which is int to 0
set isActive which is flag to true

// Invalid identifiers
set 123name which is text to "Error"    // Cannot start with number
set for which is text to "Error"        // 'for' is reserved
set user-name which is text to "Error"  // Hyphens not allowed

Statements and Expressions

Statements

Statements perform actions and don't return values:

// Display statement
display "Hello"

// Variable assignment
set count which is int to 5

// Control flow
when count is greater than 0 then
  display "Positive"
end when

Expressions

Expressions evaluate to values:

// Arithmetic expressions
set sum to 10 + 5
set product to width * height
set average to total / count

// String expressions
set greeting to "Hello, " + name
set message to "Welcome [name] to our system!"

// Boolean expressions
set is_adult to age >= 18
set can_vote to age >= 18 and is_citizen

Operators

Arithmetic Operators

set a which is int to 10
set b which is int to 3

set sum to a + b          // Addition: 13
set difference to a - b   // Subtraction: 7
set product to a * b      // Multiplication: 30
set quotient to a / b     // Division: 3.33...
set remainder to a % b    // Modulo: 1

Comparison Operators

Droe uses natural language for comparisons:

set x which is int to 10
set y which is int to 5

// Equality
when x is equal to y then display "Equal" end when
when x is not equal to y then display "Not equal" end when

// Magnitude comparisons
when x is greater than y then display "x > y" end when
when x is less than y then display "x < y" end when
when x is greater than or equal to y then display "x >= y" end when
when x is less than or equal to y then display "x <= y" end when

Logical Operators

set is_adult which is flag to age >= 18
set has_license which is flag to true

// AND
when is_adult and has_license then
  display "Can drive"
end when

// OR
when is_adult or has_permission then
  display "Can enter"
end when

// NOT
when not is_busy then
  display "Available"
end when

String Operators

set first_name which is text to "John"
set last_name which is text to "Doe"

// Concatenation
set full_name to first_name + " " + last_name

// Interpolation
set greeting to "Hello, [first_name]!"
set info to "Name: [full_name], Age: [age]"

Block Structure

Droe uses explicit end keywords to terminate blocks:

// Conditional blocks
when condition then
  // statements
end when

// Loop blocks
for each item in collection
  // statements
end for

// Module blocks
module utilities
  // module content
end module

// Action blocks
action calculate with param which is int gives int
  // statements
  give result
end action

Whitespace and Formatting

Droe is flexible with whitespace:

// Compact style
set name which is text to "Alice"
when age is greater than 18 then display "Adult" end when

// Expanded style
set name which is text to "Alice"

when age is greater than 18 then
  display "Adult"
end when

// Mixed style (recommended)
set name which is text to "Alice"
set age which is int to 25

when age is greater than 18 then display "Adult" end when

Line Breaks and Semicolons

• Statements are typically one per line
• No semicolons required
• Long statements can be broken across lines

// Single line (preferred)
set total to price * quantity + tax

// Multi-line for readability
set total to price * quantity 
  + tax 
  + shipping_cost

// Natural line breaks in conditionals
when user_age is greater than or equal to 18 
  and has_valid_id 
  and account_is_active then
  display "Access granted"
end when

Case Sensitivity

Droe is case-sensitive:

set userName which is text to "Alice"
set username which is text to "Bob"    // Different variable
set UserName which is text to "Carol"  // Also different

// Keywords must be lowercase
set count which is int to 5    // Correct
SET count WHICH IS int to 5    // Error

String Literals

Basic Strings

set message which is text to "Hello, World!"
set empty which is text to ""
set with_quotes which is text to "She said \"Hello\""

Escape Sequences

set with_newline which is text to "Line 1\nLine 2"
set with_tab which is text to "Name:\tValue"
set with_backslash which is text to "Path: C:\\Users\\Name"

Multi-line Strings

set long_text which is text to "This is a very long string 
that spans multiple lines 
for better readability"

Numeric Literals

// Integers
set count which is int to 42
set negative which is int to -10
set zero which is int to 0

// Decimals
set price which is decimal to 19.99
set negative_decimal which is decimal to -5.5
set scientific which is decimal to 1.23e10

Boolean Literals

set is_active which is flag to true
set is_hidden which is flag to false

Collections

// Lists (arrays)
set numbers which are list of int to [1, 2, 3, 4, 5]
set names which are list of text to ["Alice", "Bob", "Carol"]
set flags which are list of flag to [true, false, true]

// Empty collections
set empty_list which are list of text to []

Best Practices

1. Use Descriptive Names

// Good
set user_age which is int to 25
set total_price which is decimal to 199.99
set is_authenticated which is flag to true

// Avoid
set x which is int to 25
set temp which is decimal to 199.99
set flag1 which is flag to true

2. Consistent Formatting

// Consistent spacing around operators
set total to price + tax
set is_valid to age >= 18 and has_license

// Consistent indentation in blocks
when is_authenticated then
  display "Welcome back!"
  set last_login to current_time
end when

3. Group Related Code

// User information
set user_name which is text to "Alice"
set user_age which is int to 28
set user_email which is text to "alice@example.com"

// Calculations
set subtotal to price * quantity
set tax_amount to subtotal * tax_rate
set total to subtotal + tax_amount

4. Use Comments Wisely

// Calculate monthly payment for loan
set monthly_rate to annual_rate / 12
set num_payments to years * 12
set payment to principal * monthly_rate / (1 - (1 + monthly_rate)^(-num_payments))

display "Monthly payment: $[payment]"

Common Patterns

Input Validation

when age is less than 0 or age is greater than 150 then
  display "Invalid age"
otherwise
  display "Age is valid: [age]"
end when

Calculations with Formatting

set price which is decimal to 29.99
set quantity which is int to 3
set total to price * quantity

display "Price: $[price]"
display "Quantity: [quantity]"
display "Total: $[total]"

Error Handling Patterns

when file_exists then
  display "Processing file..."
  // Process file
otherwise
  display "Error: File not found"
end when

Next Steps

Now that you understand Droe's basic syntax, explore these topics:

• Type System - Learn about Droe's strong typing
• Variables - Variable declaration and scope
• Strings - String interpolation and manipulation
• Collections - Working with lists and arrays
• Conditionals - Control flow with when/then
• Loops - Iteration with for-each loops