Strings in GoloScript

Complete guide to string manipulation in GoloScript.

Multiline Strings

GoloScript supports multiline strings with """ syntax:

let helpText = """
Usage: myapp [OPTIONS] COMMAND

Options:
  -h, --help     Show this help message
  -v, --version  Show version information

Commands:
  start          Start the application
  stop           Stop the application
"""

println(helpText)

Use Cases: Documentation, SQL queries, JSON/XML templates, ASCII art

Escape Sequences

GoloScript supports standard escape sequences to include special characters in strings.

Available Escape Sequences

Sequence	Description	Example
`\"`	Double quote	`"He said: \"Hello\""`
`\\`	Backslash	`"C:\\Users\\Alice"`
`\n`	Newline	`"Line 1\nLine 2"`
`\t`	Tab	`"Col1\tCol2\tCol3"`
`\'`	Apostrophe (optional)	`"It\'s time"`
`\0`	Null character	`"End\0"`

Practical Examples

Double Quotes

let quote = "He said: \"Hello everyone!\""
println(quote)
# Prints: He said: "Hello everyone!"

Windows File Paths

let path = "C:\\Users\\Alice\\Documents\\file.txt"
println(path)
# Prints: C:\Users\Alice\Documents\file.txt

Multiline Text with \n

let multiline = "Line 1\nLine 2\nLine 3"
println(multiline)
# Prints:
# Line 1
# Line 2
# Line 3

Tabs

let tabbed = "Name:\t\"Alice\"\nAge:\t30\nCity:\t\"Paris\""
println(tabbed)
# Prints:
# Name:   "Alice"
# Age:    30
# City:   "Paris"

JSON with Escapes

let json = "{\"name\":\"Bob\",\"message\":\"Hello \\\"World\\\"\"}"
println(json)
# Prints: {"name":"Bob","message":"Hello \"World\""}

let parsed = fromJSON(json)
println("Name:", parsed: name())        # Bob
println("Message:", parsed: message())  # Hello "World"

Formatted JSON

let prettyJson = "{\n\t\"title\": \"Golo\",\n\t\"version\": 2.0,\n\t\"active\": true\n}"
println(prettyJson)
# Prints:
# {
#     "title": "Golo",
#     "version": 2.0,
#     "active": true
# }

All Escapes Together

let all = "Tab:\\t Newline:\\n Quote:\\\" Backslash:\\\\ SingleQuote:\\' Null:\\0End"
println(all)
# Prints: Tab:\t Newline:\n Quote:\" Backslash:\\ SingleQuote:\' Null:\0End

String Methods

Basic Methods

let text = "Hello World"

# Length
text: length()                    # 11

# Character access
text: charAt(0)                   # "H"
text: substring(0, 4)             # "Hello" (end inclusive)

# Search
text: contains("World")           # true
text: startsWith("Hello")         # true
text: endsWith("World")           # true
text: indexOf("o")                # 4
text: lastIndexOf("o")            # 7

Transformations

let text = "  Hello World  "

# Case
text: toLowerCase()               # "  hello world  "
text: toUpperCase()               # "  HELLO WORLD  "

# Whitespace
text: trim()                      # "Hello World"

# Replacement
text: replace("World", "Golo")    # "  Hello Golo  "
text: replaceAll(" ", "_")        # "__Hello_World__"

Split and Join

# Split
let words = "one,two,three": split(",")
# → ["one", "two", "three"]

# Iteration
foreach word in words {
  println(word)
}

Comparison

let str1 = "Hello"
let str2 = "HELLO"

# Case sensitive
str1 == str2                      # false

# Case insensitive
str1: equalsIgnoreCase(str2)      # true

Type Conversions

GoloScript offers several approaches for converting strings to numbers, each with its advantages and use cases.

String → Int Conversion

There are 4 ways to convert a string to an integer:

1. `int()` Function - Throws Exception

# Imperative style
try {
  let num = int("42")
  println("Result:", num)  # 42
} catch (e) {
  println("Error:", e)
}

Characteristics:

Global builtin function
Throws exception on error
Requires try-catch for error handling
Usage: imperative code where error is exceptional

2. `toInt()` Method - Throws Exception

# Object-oriented style
try {
  let num = "123": toInt()
  println("Result:", num)  # 123
} catch (e) {
  println("Error:", e)
}

Characteristics:

Method on String objects
Throws exception on error
Object-oriented syntax
Requires try-catch for error handling

3. `parseInt()` Function - Returns Result

import gololang.Errors

let result = parseInt("999")
println("Result:", result)

if isOk(result) {
  println("Value:", result: value())  # 999
}

if isError(result) {
  println("Error:", result: message())
}

Characteristics:

Function from gololang.Errors module
Returns Result[Int, String]
No exception, error as value
Allows functional composition

4. `either()` Function - Pattern Matching (⭐ RECOMMENDED)

import gololang.Errors

let inputs = array("42", "invalid", "-100", "xyz", "0")

foreach input in inputs {
  let result = parseInt(input)
  either(result,
    |value| -> println("✓", input, "->", value),
    |error| -> println("✗", input, "-> Error")
  )
}

Characteristics:

Handles both cases (success/failure) elegantly
No if/else needed
Declarative and expressive style
Best practice for Result

String → Float Conversion

GoloScript offers 3 approaches for converting a string to floating-point number:

1. `float()` Function - Throws Exception

try {
  let f = float("3.14159")
  println("Result:", f)  # 3.14159
} catch (e) {
  println("Error:", e)
}

2. `toFloat()` Method - Throws Exception

try {
  let f = "2.71828": toFloat()
  println("Result:", f)  # 2.71828
} catch (e) {
  println("Error:", e)
}

3. `parseFloat()` Function - Result (⭐ RECOMMENDED)

import gololang.Errors

let inputs = array("1.618", "bad", "-273.15", "0.0", "xyz")

foreach input in inputs {
  let result = parseFloat(input)
  either(result,
    |value| -> println("✓", input, "->", value),
    |error| -> println("✗", input, "-> Error")
  )
}

Comparison and Recommendations

Approach	Style	Error Handling	Use Case
`int()` / `toInt()`	Imperative	Exception	Exceptional error, imperative code
`float()` / `toFloat()`	Imperative	Exception	Exceptional error, imperative code
`parseInt()` + `either()`	Functional	Result	⭐ Validation, parsing user input (recommended)
`parseFloat()` + `either()`	Functional	Result	⭐ Validation, parsing user input (recommended)

General Recommendation:

Use parseInt() / parseFloat() + either() for safer and more expressive code
These functions allow functional composition with mapResult, flatMapResult, etc.
Error as value avoids unexpected exceptions

Type Detection

let input = "123"

# Checking
input: isNumeric()                # true
input: isInt()                    # true
input: isFloat()                  # false (it's an integer)

let decimal = "3.14"
decimal: isNumeric()              # true
decimal: isFloat()                # true

Convert to Boolean

"true": toBool()                  # true
"false": toBool()                 # false

# Contextual check
let answer = "yes"
if answer: toLowerCase() == "yes" or answer: toLowerCase() == "true" {
  # Treat as true
}

Utility Functions

Email Validation

function isValidEmail = |email| {
  let trimmed = email: trim()
  if not trimmed: contains("@") {
    return false
  }
  let parts = trimmed: split("@")
  if parts: length() != 2 {
    return false
  }
  let domain = parts: get(1)
  return domain: contains(".")
}

isValidEmail("john@example.com")   # true
isValidEmail("invalid.email")      # false

Data Type Detection

function whatIsIt = |item| {
  return match {
    when item: contains("@") then "email"
    when item: startsWith("http://") then "HTTP URL"
    when item: startsWith("https://") then "HTTPS URL"
    when item: startsWith("+33") then "French phone"
    otherwise "unknown"
  }
}

whatIsIt("john@example.com")       # "email"
whatIsIt("https://example.com")    # "HTTPS URL"

Word Counter

function countWords = |text| {
  let trimmed = text: trim()
  if trimmed: isEmpty() {
    return 0
  }
  return trimmed: split(" "): length()
}

countWords("Hello world from Golo")  # 4

Title Case

function toTitleCase = |text| {
  let words = text: toLowerCase(): split(" ")
  var result = ""
  var first = true

  foreach word in words {
    if not first {
      result = result + " "
    }
    if word: length() > 0 {
      let firstChar = word: charAt(0): toUpperCase()
      let rest = word: substring(1)
      result = result + firstChar + rest
    }
    first = false
  }

  return result
}

toTitleCase("hello world")         # "Hello World"

Truncate

function truncate = |text, maxLen| {
  if text: length() <= maxLen {
    return text
  }
  if maxLen <= 3 {
    return text: substring(0, maxLen - 1)
  }
  return text: substring(0, maxLen - 4) + "..."
}

truncate("This is a long sentence", 15)  # "This is a lo..."

HTML Sanitization

function sanitize = |input| {
  return input: trim()
    : replaceAll("<", "&lt;")
    : replaceAll(">", "&gt;")
}

sanitize("<script>alert('xss')</script>")
# "&lt;script&gt;alert('xss')&lt;/script&gt;"

Slugification

function slugify = |text| {
  return text: toLowerCase()
    : trim()
    : replaceAll(" ", "-")
}

slugify("Hello World")             # "hello-world"

File Extension

function getFileExtension = |filename| {
  let dotIndex = filename: lastIndexOf(".")
  if dotIndex == -1 {
    return ""
  }
  return filename: substring(dotIndex + 1)
}

getFileExtension("document.pdf")   # "pdf"
getFileExtension("readme")         # ""

Best Practices

✅ Do

Always validate before conversion

if input: isInt() {
  let num = input: toInt()
  # Use num safely
}

Use trim() to clean input
```
let clean = userInput: trim()
```
Prefer equalsIgnoreCase() for case-insensitive comparison
```
if answer: equalsIgnoreCase("yes") {
  # ...
}
```

❌ Don’t

Don’t convert without checking

# ❌ Risk of error
let num = input: toInt()

# ✅ Safe
if input: isInt() {
  let num = input: toInt()
}

Don’t forget isEmpty()

# ❌ Error if empty
let words = text: split(" ")

# ✅ Check first
if not text: trim(): isEmpty() {
  let words = text: split(" ")
}

Summary

Strings in GoloScript offer:

Multiline: """ syntax for long texts
Rich methods: 20+ useful methods
Safe conversions: isInt(), isFloat(), toBool()
Utilities: Validation, sanitization, transformation

Recommendation: Always validate before converting, use method chaining for elegant code.

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Strings in GoloScript

Multiline Strings

Escape Sequences

Available Escape Sequences

Practical Examples

Double Quotes

Windows File Paths

Multiline Text with \n

Tabs

JSON with Escapes

Formatted JSON

All Escapes Together

String Methods

Basic Methods

Transformations

Split and Join

Comparison

Type Conversions

String → Int Conversion

1. int() Function - Throws Exception

2. toInt() Method - Throws Exception

3. parseInt() Function - Returns Result

4. either() Function - Pattern Matching (⭐ RECOMMENDED)

String → Float Conversion

1. float() Function - Throws Exception

2. toFloat() Method - Throws Exception

3. parseFloat() Function - Result (⭐ RECOMMENDED)

Comparison and Recommendations

Type Detection

Convert to Boolean

Utility Functions

Email Validation

Data Type Detection

Word Counter

Title Case

Truncate

HTML Sanitization

Slugification

File Extension

Best Practices

✅ Do

❌ Don’t

Summary

1. `int()` Function - Throws Exception

2. `toInt()` Method - Throws Exception

3. `parseInt()` Function - Returns Result

4. `either()` Function - Pattern Matching (⭐ RECOMMENDED)

1. `float()` Function - Throws Exception

2. `toFloat()` Method - Throws Exception

3. `parseFloat()` Function - Result (⭐ RECOMMENDED)