101 lines
2.2 KiB
Standard ML
Executable file
101 lines
2.2 KiB
Standard ML
Executable file
#!/usr/bin/env fun
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/**
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* This file is part of the Fun programming language.
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* https://fun-lang.xyz/
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*
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* Copyright 2025 Johannes Findeisen <you@hanez.org>
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* Licensed under the terms of the Apache-2.0 license.
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* https://opensource.org/license/apache-2-0
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*/
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// Type Safety demonstration in Fun
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print("== Dynamic variable (untyped) ==")
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x = 100
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print(typeof(x)) // -> "Number"
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print(x) // -> 100
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x = "hello"
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print(typeof(x)) // -> "String"
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print(x) // -> "hello"
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print("")
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print("== Typed variables remain type-stable ==")
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// Strings must always be strings
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string s = "hello"
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print(typeof(s)) // -> "String"
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print(s) // -> "hello"
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// s = 42 // Uncomment to see runtime TypeError: expected String
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// Booleans are Numbers constrained to 0 or 1 (clamped)
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boolean flag = 0
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print(typeof(flag)) // -> "Number"
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print(flag) // -> 0
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flag = 2 // will be clamped to 1
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print(flag) // -> 1
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// flag = "no" // Uncomment to see runtime TypeError: expected Number for boolean
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// number is a signed 64-bit integer and must remain Number
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number n = 123
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print(typeof(n)) // -> "Number"
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n = 456
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print(n) // -> 456
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// n = "oops" // Uncomment to see runtime TypeError: expected Number
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print("")
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print("== Integer width clamping ==")
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// Signed 8-bit: range [-128..127]
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int8 si = 130 // clamps to 127
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print(si) // -> 127
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si = -200 // clamps to -128
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print(si) // -> -128
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// Unsigned 8-bit: range [0..255]
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uint8 u = 255
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print(u) // -> 255
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u = 300 // clamps to 255
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print(u) // -> 255
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// u = "bad" // Uncomment to see runtime TypeError: expected Number
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print("")
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print("== Nil-typed variables must stay Nil ==")
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nil nn = nil
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print(typeof(nn)) // -> "Nil"
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// nn = 0 // Uncomment to see runtime TypeError: expected Nil
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print("")
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print("Done. Uncomment lines above to see type errors in action.")
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/* Expected output:
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== Dynamic variable (untyped) ==
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Number
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100
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String
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hello
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== Typed variables remain type-stable ==
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String
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hello
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Number
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0
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0
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Sint64
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456
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== Integer width clamping ==
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-126
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56
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255
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44
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== Nil-typed variables must stay Nil ==
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Nil
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Done. Uncomment lines above to see type errors in action.
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*/
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