TOC: Crystal Programming

• Introduction
  1. Crystal Language
  2. Crystal Shards (3rd party libraries)
  3. How to install 3rd party shards?
  4. Install Crystal
  5. Crystal in Docker on Linux
  6. Hello World (puts)
  7. Run Crystal source code
  8. Compile Crystal to executable
  9. Speed of Crystal
  10. Hello World (print)
  11. Hello Name (variables)
  12. Hello Name with interpolation
  13. Interpolation
  14. Escaping - Alternative quote as delimiters
  15. Debugging print p!
  16. Comments
  17. Code formatting
  18. Types - typeof
  19. Compound Types - typeof
  20. Add numbers - concatenate strings
  21. Add mixed strings and Integers
  22. Numeric Operators
  23. Methods of Int32
  24. Methods of Float64
  25. Program name
  26. Command line arguments - ARGV
  27. Early exit
  28. Rectangle
  29. True values
  30. Math - PI
  31. Read from STDIN
  32. Read number from STDIN
  33. Interactive environments
  34. Crystal one-liners
  35. Crystal and random numbers
  36. Exercise: Hello World
  37. Exercise: Hello Name - STDIN
  38. Exercise: Hello Name - ARGV
  39. Exercise: Circle STDIN
  40. Exercise: Circle ARGV
  41. Exercise: Calculator STDIN
  42. Exercise: Calculator ARGV
  43. Exercise: Age limit
• Strings
  1. Strings intro
  2. Length or size of a string
  3. Locate substring (index, rindex)
  4. Reverse a string
  5. Substring, range of characters
  6. String includes another string
  7. String starts with
  8. String ends with
  9. Replace part of a string (substitute)
  10. Is the string empty or blank?
  11. Iterate over characters of a string
  12. Type conversion from string to float, to int
  13. Converting string to integer or float
  14. Split String
  15. String Transliteration
  16. String Builder
  17. sprintf and %
  18. Split to the same string length
  19. Split characters
  20. printf
  21. Here documents
• Conditionals
  1. Comparison Operators
  2. Spaceship operator
  3. if statement
  4. elsif
  5. unless statement
  6. Suffix if
  7. Suffix unless
  8. Logical operators
  9. Truth-table
  10. case / when
  11. case of types
  12. Ternary operator and or to set default value
  13. Exercise: Number Guessing game - level 0
  14. Solution: Number Guessing game - level 0
• Loops
  1. loop
  2. loop controls (next, break)
  3. while
  4. until
  5. Exercise: Number guessing game
  6. Solution: Number guessing game
• Arrays
  1. Arrays intro
  2. Array elements - indexing
  3. Array iterate over (each, each_with_index)
  4. Array push, append, <<
  5. Empty array
  6. Count digits
  7. Operations on arrays
  8. Add arrays
  9. Repeat arrays
  10. Select (filter, grep)
  11. Reject (negative filter, grep)
  12. Transform with map
  13. Sample from array
  14. Shuffle array
  15. join
  16. Remove nil elements
  17. Create Array with nil
  18. Does array include a value
  19. Delete element from array by value
  20. Delete element from array by location
  21. Insert element into array at location
  22. Arrays shift - remove first element
  23. Arrays uniq elements
  24. First element of the array
  25. Permutations
• Hash
  1. Hash intro
  2. Count words
  3. Create empty hash
  4. Hash and types
  5. Hash get value, get default value
  6. Merge hashes
  7. Delete - remove an element from a hash
  8. Reject - remove an element from a hash
  9. Clear - empty a hash
  10. Select - keep certain key-value pairs
  11. Multi-dimensional hash
  12. Dig a hash
• Files
  1. Files intro
  2. Read from file (slurp)
  3. Read lines into array
  4. Read file line-by-line
  5. Write to file
  6. Append to file
  7. Does file exist?
  8. Size of file?
  9. Last Modified date of file?
  10. Counter
  11. Multi Counter JSON
  12. Multi Counter YAML
• Directories
  1. List directory content
  2. List directory tree
  3. Get Current working directory (cwd, pwd)
  4. Temporary directory
  5. Tempdir function
  6. Join / concatenate file system path
  7. Join / concatenate file system path
  8. Path from string
  9. Expand Path
• Sets
  1. Create empty set
  2. Set examples
• Functions
  1. Functions and methods
  2. Function return value
  3. Function parameter passing
  4. Function parameter default value
  5. Wrong number of arguments
  6. Any number of arguments (splat, *)
  7. Manually separate
  8. Tuple from
  9. Array overload
  10. Multiple dispatch
  11. Implicit return value
  12. Return Type definition
  13. Type or Nil
  14. Yield
  15. Yield with parameters
  16. Block and parameters
• Tuples and Named Tuples
  1. Create Tuple
  2. Create Named Tuple
  3. Access fields of Named Tuple
  4. Named Tuple with non-alphanumeric fields
  5. Named Tuple with optional field
• Structs
  1. Empty struct
  2. Initialize immutable struct
  3. Initialize immutable struct - shorthand
  4. Immutable struct with getters
  5. Immutable struct with getter macro
  6. Mutable Struct with setter
  7. Mutable Struct with property macro
  8. Struct with optional attributes
  9. Struct with default value
  10. Struct pass-by-value
  11. Struct from JSON
  12. Struct from JSON - upper case
  13. Struct both from JSON and initialize
  14. Struct from JSON - manual parsing
  15. Multi-level struct manually
  16. Multi-level struct from JSON
  17. Struct from JSON with extra data
  18. Struct from JSON missing data (optional fields)
  19. Extend struct
  20. Extend other structs
• Classes
  1. Empty Class definition
  2. Class with attributes
  3. Class with getters
  4. Class with setter
  5. Class with getters and setter (property)
  6. Class with property with default value
  7. Class with declared getter and default value
  8. Class with declared getter
  9. Serialize Crystal-lang class to/from JSON from_json to_json
  10. Compare objects for equality
  11. Singleton using class properties
  12. Singleton using class properties with default values
  13. Class monkey-path add method
  14. Stringification to_s
• Regexes
  1. Alternate delimiter matching slashes
  2. Substitute
  3. gsub
• Testing
  1. Testing 1
  2. Testing with Spec
• Modules
  1. Namespace
  2. Extend class - include module
• JSON
  1. JSON (to_json, parse)
  2. JSON to NamedTuple
  3. Reading a JSON file
  4. JSON to Array
• Range
  1. Range using dots
  2. Range using a class
  3. Range - sum
  4. Range - count
  5. Range and loop controls
  6. Range with step
  7. Range to Array
• Random
  1. rand
  2. Random in other parts of Crystal
  3. Random as a class
  4. Random - seed
• YAML
  1. Parse YAML
• Exception Handling in Crystal-lang
  1. Catch exception - begin, rescue
  2. Raise exception
• Logging
  1. Crystal logging
• SQLite
  1. Try SQLite
  2. Multi-counter with SQLite
  3. SQLite last_id last_insert_id
  4. SQLite UPDATE row_affected
  5. SQLite exception handling (during INSERT)
  6. SQLite all
  7. SQLite in memory
• Time
  1. Dates and Time
  2. Sleep
  3. Time difference or Time::Span
  4. Elapsed time
  5. Timestamp formatting
  6. Add timespan
  7. Time Types
• CLI
  1. ARGV
  2. Usage statement and exit
  3. Command line Option Parser (argparse, GetOpts)
  4. Pass parameters to OptionParser
  5. Order of parsing
• HTTP Client
  1. HTTP Client example
  2. Parse URL (URI)
  3. HTTP::Request GET
  4. HTTP::Request POST
• Process
  1. Execute external program (system)
  2. Execute external program (backtick)
  3. Execute external program (Process)
  4. Execute external program (capture)
  5. Execute external program (capture)
  6. Abort
• Concurrency
  1. Send and receive
  2. Concurrent HTTP request
• Kemal
  1. About Kemal
  2. Kemal Install
  3. Hello World
  4. Testing Hello World
  5. Kemal Autorestart (autoreload)
  6. Kemal GET parameters
  7. Kemal POST parameters
  8. Kemal Route parameters
  9. Kemal ECR Templates
  10. Kemal with Jinja templates
  11. Kemal Elapsed time
  12. Accept GET, POST, and route parameter in the same POST route
  13. Kemal indicate 404
  14. Kemal Styling 404 pages
  15. Kemal set headers (change content-type)
  16. Kemal redirect
  17. Kemal in Docker
• Other
  1. Sequence
  2. Check if variable is nil?
  3. Single quotes vs double quotes
  4. No type-checking?
  5. Divide by zero is Infinity
  6. Require other files
  7. List Methods
  8. Checking the slides
  9. Crystal mine
  10. Ameba Linter
  11. Gravatar
  12. Try Crystal
  13. STDERR, STDOUT
  14. Return Boolean
  15. Symbols
  16. Docspec
  17. require
  18. Constants
  19. Multiple assignment
  20. Chained assignment
  21. Int methods: Times
  22. Int64 Zero
  23. Question mark: ?
  24. Exclamation mark: !
  25. Ampersand: &
  26. STDIN don't accept nil
  27. Math
  28. Proc
  29. Enums
  30. Type of array elements
  31. Environment variables
  32. Int32 or Nil
  33. Resources
• Crystal from 0 to Web site
  1. Crystal from 0 to Web site
  2. Background
  3. Why?
  4. I can do better
  5. How to learn
  6. When
  7. Shardbox
  8. What did I learn?
  9. Crystal is fun
  10. Shards
  11. Code formatter
  12. Ameba - Linter
  13. Spectator - testing framework
  14. Code coverage
  15. CI - GitHub Actions
  16. The language
  17. What do ? and ! mean?!
  18. Emojis and Unicode characters 💎
  19. Meaning of ?
  20. Meaning of !
  21. Web framework?
  22. Amber Framework
  23. Lucky Framework
  24. Kemal
  25. Crinja
  26. Shardbox
  27. Future
  28. Thank you - QA ?!?!