IO

Functions for input/output operations. This module provides primitive I/O actions that interact with the external environment, such as printing to standard output, reading from standard input, and reading/writing files. All I/O operations are wrapped in the IO type to maintain purity in the language.

println_string

Print a string followed by a newline.

Output the given string to standard output, appending a newline character at the end.

println_string : string -> IO<unit>println_string : string -> IO<unit>

print_string

Print a string without a trailing newline.

Output the given string to standard output. No newline is appended.

print_string : string -> IO<unit>print_string : string -> IO<unit>

println_int32

Print a 32-bit integer followed by a newline.

Convert the given int32 value to its decimal text representation and output it to standard output, appending a newline.

println_int32 : int32 -> IO<unit>println_int32 : int32 -> IO<unit>

print_int32

Print a 32-bit integer without a trailing newline.

Convert the given int32 value to its decimal text representation and output it to standard output.

print_int32 : int32 -> IO<unit>print_int32 : int32 -> IO<unit>

println_int64

Print a 64-bit integer followed by a newline.

Convert the given int64 value to its decimal text representation and output it to standard output, appending a newline.

println_int64 : int64 -> IO<unit>println_int64 : int64 -> IO<unit>

print_int64

Print a 64-bit integer without a trailing newline.

Convert the given int64 value to its decimal text representation and output it to standard output.

print_int64 : int64 -> IO<unit>print_int64 : int64 -> IO<unit>

println_bignum

Print an arbitrary-precision integer followed by a newline.

Convert the given bignum value to its decimal text representation and output it to standard output, appending a newline.

println_bignum : bignum -> IO<unit>println_bignum : bignum -> IO<unit>

print_bignum

Print an arbitrary-precision integer without a trailing newline.

Convert the given bignum value to its decimal text representation and output it to standard output.

print_bignum : bignum -> IO<unit>print_bignum : bignum -> IO<unit>

println_bool

Print a boolean value followed by a newline.

Output the string representation (true or false) of the given boolean to standard output, appending a newline.

println_bool : bool -> IO<unit>println_bool : bool -> IO<unit>

print_bool

Print a boolean value without a trailing newline.

Output the string representation (true or false) of the given boolean to standard output.

print_bool : bool -> IO<unit>print_bool : bool -> IO<unit>

println_char

Print a character followed by a newline.

Output the given character to standard output, appending a newline.

println_char : char -> IO<unit>println_char : char -> IO<unit>

print_char

Print a character without a trailing newline.

Output the given character to standard output.

print_char : char -> IO<unit>print_char : char -> IO<unit>

println_float

Print a 32-bit floating-point number followed by a newline.

Convert the given float value to its decimal text representation and output it to standard output, appending a newline.

println_float : float -> IO<unit>println_float : float -> IO<unit>

print_float

Print a 32-bit floating-point number without a trailing newline.

Convert the given float value to its decimal text representation and output it to standard output.

print_float : float -> IO<unit>print_float : float -> IO<unit>

println_double

Print a 64-bit floating-point number followed by a newline.

Convert the given double value to its decimal text representation and output it to standard output, appending a newline.

println_double : double -> IO<unit>println_double : double -> IO<unit>

print_double

Print a 64-bit floating-point number without a trailing newline.

Convert the given double value to its decimal text representation and output it to standard output.

print_double : double -> IO<unit>print_double : double -> IO<unit>

println_nat

Print a natural number followed by a newline.

Convert the given nat value to its decimal text representation (via unpack) and output it to standard output, appending a newline.

println_nat : nat -> IO<unit>println_nat : nat -> IO<unit>

print_nat

Print a natural number without a trailing newline.

Convert the given nat value to its decimal text representation (via unpack) and output it to standard output.

print_nat : nat -> IO<unit>print_nat : nat -> IO<unit>

__eval_io

Evaluate an IO action and extract its result.

Internal primitive that runs the given IO action, returning the wrapped value of type v. This is the eliminator for the IO type.

__eval_io : IO<v> -> v__eval_io : IO<v> -> v

return

Lift a pure value into the IO type.

Wrap the given value in an IO action that, when evaluated, produces that value. This is the introduction form for the IO type.

return : v -> IO<v>return : v -> IO<v>

FileIOResult

type

Opaque type representing the result of a file I/O operation.

This type is used internally by read_file and write_file to communicate both the status code and the result value from the runtime back to Coal code.

FileIOError

type

Errors that can occur during file I/O operations.

read_file

Read the contents of a file.

Open the file at the given path, read its contents into a string, and return the result wrapped in IO. On success the result is Ok(string); on failure it is Err(FileIOError).

read_file : string -> IO<Result<string, FileIOError>>read_file : string -> IO<Result<string, FileIOError>>

write_file

Write data to a file.

Open the file at the given path and write the given string data to it. Returns None on success, or Some(FileIOError) on failure.

write_file : string -> string -> IO<Option<FileIOError>>write_file : string -> string -> IO<Option<FileIOError>>

readln

Read a line of text from standard input.

Read characters from stdin until a newline is encountered, and return the resulting string (excluding the trailing newline).

readln : unit -> IO<string>readln : unit -> IO<string>

random

Generate a random floating-point number.

Return a pseudo-random double value uniformly distributed in the range [0.0, 1.0).

random : unit -> IO<double>random : unit -> IO<double>

__return_io

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