language-deep-dive5 min

Types and Conversions

Clean Language is strictly typed — every variable has exactly one type and the compiler enforces it. Understanding the four core types and how to convert between them is the foundation for writing type-correct code.

The four core types — string, integer, number, boolean — each have conversion methods:

start:\n    string age_text = "28"\n    integer age = age_text.toInteger()\n    number score = 94.7\n    boolean passing = score >= 60.0\n\n    print("Age: " + age.toString())\n    print("Score: " + score.toString())\n    print("Passing: " + passing.toString())

Age: 28\nScore: 94.7\nPassing: true

Every type has .toString() for concatenation. Use .toInteger() to convert a string to a whole number and .toNumber() to convert to a decimal. The compiler catches type mismatches — adding an integer to a string without converting first is a compile error, not a runtime surprise.

Convert between numeric types for mixed arithmetic:

start:\n    integer count = 5\n    number ratio = count.toNumber() / 2.0\n    print("Ratio: " + ratio.toString())\n\n    string price_str = "19.99"\n    number price = price_str.toNumber()\n    number with_tax = price * 1.1\n    print("Total: " + with_tax.toString())

Ratio: 2.5\nTotal: 21.989

.toNumber() converts an integer to a decimal for arithmetic that produces fractions. .toInteger() converts in the other direction, truncating the decimal part. Always convert explicitly — Clean Language never coerces types silently.

Quick recap

The four core types: string, integer, number, boolean
Use .toString() to convert any type to a string for concatenation
Use .toInteger() and .toNumber() to parse string values from user input
The compiler prevents type mixing — conversion is always explicit