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system.md

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Supported standard system values

See the BQN specification for full descriptions of the following values.

function notes
•BQN
•ReBQN Supported options: repl; primitives; system that's not "safe"
•primitives
•_while_
•Import
•state
•args
•path
•name
•wdpath
•Exit
•file Fields: path, At, List, Bytes, Chars, Lines, Type, Exists, Name, Parent, MapBytes, CreateDir, RealPath, Rename, Remove, Created, Modified, Accessed, Size
•FChars
•FBytes
•FLines
•Out
•Show
•Repr
•Fmt
•ParseFloat Should exactly round floats with up to 17 significant digits, but won't necessarily round correctly with more
•term Fields: Flush, RawMode, CharB, CharN; has extensions
•SH See •SH
•FFI see FFI
•platform
•Type
•Glyph
•Decompose
•ns
•HashMap
•UnixTime second-level precision
•MonoTime up to nanosecond level precision, depending on system support
•Delay
•_timed
•math Fields: Acos, Acosh, Asin, Asinh, Atan, Atan2, Atanh, Cbrt, Comb, Cos, Cosh, Erf, ErfC, Expm1, Fact, GCD, Hypot, LCM, Log10, Log1p, Log2, LogFact, Sin, Sinh, Sum, Tan, Tanh; ⁼ supported for trigonometry functions and between Expm1 & Log1p
•MakeRand uses wyhash, not cryptographically secure; Result fields: Range, Deal, Subset
•rand seeds with system time (can be hard-coded by setting the C macro RANDSEED), same algorithm as •MakeRand
•bit Fields: _cast; casting an sNaN bit pattern to a float is undefined behavior

CBQN-specific system values and extensions

•term

•term.OutRaw and •term.ErrRaw output the given bytes directly to the specific stream, without any trailing newline. May be removed once a proper interface for stream I/O has been made.

•GetLine

Ignores its argument and returns one line of stdin.

Might be removed, moved, or renamed in the future.

•Hash

Get the hash of 𝕩.

Monadically, use the global secret value which will differ between CBQN sessions.

Dyadically, use the integer left argument as the seed. Will be the same between multiple CBQN sessions, but may change between CBQN versions.

•Cmp

Compare arguments. Equal to ((⊑⍋-⍒)⋈).

•FromUTF8

Convert the argument UTF-8 byte array (or character array consisting of codepoints 0-255) to a string.

May be removed or renamed in the future.

•ToUTF8

Convert the argument character list to a UTF-8-encoded byte array, represented as a list of characters with codepoints 0-255.

May be removed or renamed in the future.

•CurrentError

Get the current error message while within the catch side of ⎊. Dynamically-scoped.

Argument must not be a namespace, as that is reserved for future changes.

•internal

Namespace of various internal functions. May change at any time.

name description
•internal.GC Run a garbage collection cycle
•internal.Type Name of the internal type for an object
•internal.ObjFlags Monadically, get the flags of 𝕩. Dyadically, set the flags of 𝕩 to 𝕨.
•internal.ElType Element size type identifier; see enum ElType
•internal.Keep Require the argument to stay alive up to this point in the program. Returns the argument, but without signaling to possible optimizations that the input and output will be equal
•internal.PureKeep •internal.Keep but marked as a pure function
•internal.PureShow •Show but marked as a pure function (which it isn't, but it's useful for debugging)
•internal.Refc Reference count of the argument, if it's heap-allocated
•internal.IsPure Whether the vm considers the argument pure (i.e. it can execute it safely for computing fills)
•internal.Info General internal info about the object; a left argument of 1 gives more details
•internal.HeapDump Create a heap dump file; saves to •wdpath-relative path 𝕩 or CBQNHeapDump if 𝕩 isn't an array
•internal.HeapStats If argument is @, returns ⟨total heap size ⋄ used heap size⟩. If argument is a string, prints the equivalent of )mem the-string
•internal.HasFill Returns whether the argument has a fill element (may give 0 even if 1↑0⥊𝕩 doesn't error in some CBQN configurations)
•internal.WithFill Return an array with the elements & shape of 𝕩, but with the fill element set to (the fill version of) 𝕨
•internal.Squeeze Try to convert the argument to its most compact representation; result may have fill updated to 0 or ' '. (input is left unchanged)
•internal.DeepSqueeze Try to convert the argument and all its subarrays to its most compact representation; won't squeeze namespace fields
•internal.ListVariations List the possible type variations of the argument array
•internal.Variation Convert 𝕩 to the variation specified in 𝕨
•internal.ClearRefs Clear references •internal.Variation made for *Inc variations
•internal.Unshare Get a unique, reference count 1 version of the argument; recursively unshares array items, doesn't touch namespaces
•internal.EEqual Exactly equal (𝕨≡𝕩 but NaN equals NaN)
•internal.Indistinguishable Semantically indistinguishable (•internal.EEqual, plus checking fills)
•internal.Temp Place to test new features or temporarily expose some internal function
•internal.Properties Various build properties
•internal.Validate Validate that 𝕩 has correct flags set

FFI

Currently there is no support for nested pointers, and limited support of structs.

That is, the supported types are:

  • scalars (e.g. i8, u64);
  • pointers to scalars (e.g. *i8, &u64);
  • conversions of either scalars, pointers to scalars, or opaque pointers (e.g. u64:i32, *i64:i32, *:i8, **:c8);
  • arrays of scalars or structs (e.g. [2]i32, [4]{i32,i32});
  • structs of any of the above (except &-pointers) or other structs (e.g. {*i8,*{*u32:i8,u64:i32}}), except structs that are within & themselves cannot contain any pointers other than converted opaque pointers (e.g. *{*i32,u64}, &{*:i32,u64}, and &{i32,u64} are fine, but &{*i32,u64} is not);
  • the a type, which maps to BQNV from bqnffi.h (example usage in FFI tests).

•SH

The left argument can be a namespace, providing additional options.

Accepted fields:

  • stdin⇐"abcd" passes in stdin to the program; by default, it will be UTF-8 encoded.
  • raw⇐1 will make stdout/stderr return raw bytes (represented as characters with codepoints 0 to 255), and, if given, interpret stdin as such too.
   ¯1↓1⊑{stdin⇐@+20‿100‿200‿250,raw⇐1} •SH ⟨"xxd"⟩
"00000000: 1464 c8fa                                .d.."
   @-˜ 1⊑{raw⇐1} •SH ⟨"printf", "\x00\x80\xff\xfe\xee"⟩
⟨ 0 128 255 254 238 ⟩

These •SH extensions may change in the future if a different interface is standardized.