TinyAPL

TinyAPL (read like tiny apple) is a tiny APL dialect and interpreter in Haskell. It is being implemented as a series of articles available here.

Featured on the Array Cast!

• Part 1: Introduction & Arrays
• Part 2: Functions & Operators
• Part 3: More Primitives
• Part 4: Finally, Parsing!
• Part 5: Array Notation and Reductions
• Part 6: Tests, Docs, Each
• Part 7: Quads, Key, Index
• Part 8: All About Rank, and a Web Interface
• Part 9: More Tacit!
• Part 10: Wraps, Structs, a Standard Library
• Part 11: Bases and Searching
• Part 12: At Depth and Ordering
• Part 13: The Biggest Mistake, The Biggest Change
• Part 14: (Wrap Your Head Around) Dictionaries
• Part 15: Extra Arguments

Documentation is available here and you can run the latest interpreter here

Features

Marked features are supported, unmarked features are planned

• Types
  • Arrays
    • complex numbers
    • unicode characters
    • boxes (nested arrays)
  • Functions
  • Monadic Operators ("Adverbs")
  • Dyadic Operators ("Conjunctions")
• Syntax
  • number literals
    • decimal point .
    • negative sign ¯
    • exponent notation ⏨
    • complex notation ᴊ
    • complex phase notation? ∠
    • infinities ∞
  • character literals '
  • string literals "
    • escapes with ⍘
      • ⍘⍘ -> ⍘
      • ⍘" -> "
      • ⍘n -> newline
      • ⍘r -> carriage return
      • ⍘t -> tab
      • ⍘{22be} -> unicode
  • names
    • array names (abc)
    • function names (Abc)
    • monadic operator names (_Abc)
    • dyadic operator names (_Abc_)
  • assignment ←
  • dfns/dops
    • multiple statements ⋄
    • guards :
    • early return ■
    • dfns {...}, dadvs _{...}, dconjs _{...}_
    • refer to arguments and operands: ⍺ left argument, ⍵ right argument, ⍺⍺ left array operand, ⍶⍶ left function operand, ⍵⍵ right array operand, ⍹⍹ right function operand
    • recursion: ∇ recurse function, _∇ recurse adverb, _∇_ recurse conjunction
  • comments ⍝
    • inline comments? ⟃/⟄
  • console I/O with ⎕ and ⍞
  • array notation ⟨/⋄/⟩ and [/⋄/]
  • trains and modifier trains [_]⦅/⋄/⦆[_]
  • multiple statements in an expression (/⋄/)
  • ternary expressions ⍰/⍠
• primitives
  • nouns
    • ⍬ empty vector
    • ∻ empty dictionary
    • ⦻ null
    • ∅ nan
  • number functions
    • + conjugate
    • + add
    • - negate
    • - subtract
    • × direction
    • × multiply
    • ÷ reciprocal
    • ÷ divide
      • 0÷0 is 1
      • x÷0 is an error
    • * exponential
    • * power
    • ⍟ ln
    • ⍟ log
      • 1⍟1 is 1
      • 1⍟y is an error
      • x⍟0 is an error
    • √ square root
    • √ root
    • ⌊ floor
    • ⌊ minimum
    • ⌈ ceiling
    • ⌈ maximum
    • ⸠ round
    • ⸠ round to nearest
    • ⌹ matrix inverse
    • ⌹ matrix divide
    • ! factorial/gamma
    • ! binomial
    • | magnitude
    • | remainder
    • ∨ greatest common divisor
    • ∧ least common multiple
    • ⊕ cartesian (x⊕y is $x + iy$)
    • ⊕ pure imaginary (⊕y is $iy$)
    • ⊗ polar (x⊗y is $xe^{iy}$)
    • ⊗ unit polar (⊗y is $e^{iy}$)
    • ∡ phase
    • ∡ atan2
    • ℜ real part
    • ℑ imaginary part
    • ⧺ increment
    • ⵧ decrement
    • ⵧ span
    • ⊥ decode
    • ⊥ base 2 decode
    • ⊤ encode
    • ⊤ base 2 encode
  • boolean functions
    • = equals
    • ≠ not equals
    • < less
    • ≤ less or equal
    • ≥ greater or equal
    • > greater
    • ≡ identical
    • ≢ not identical
    • ⊲ precedes (TAO less)
    • ⊴ precedes or identical (TAO less or equal)
    • ⊵ succeeds or identical (TAO greater or equal)
    • ⊳ succeeds (TAO greater)
    • ∧ and
    • ∨ or
    • ⍲ nand
    • ⍱ nor
    • ~ not
  • character functions
    • ⌊ lowercase
    • ⌈ uppercase
    • | case fold
    • × case
  • set functions
    • ∪ unique
    • ∪ union
    • ∩ intersection
    • ~ difference
    • § symmetric difference
    • ≠ nub sieve
    • multisets?
  • property functions
    • ⍳ index of
    • ⍸ interval index
    • ∊ element of
    • ⍷ find
    • ⋷ mask
    • ⋵ histogram (inverse of where)
    • ⋵ count
    • ≡ depth
    • ⍴ shape
    • ≢ tally
    • ϼ rank
  • array creation functions
    • ⍳ index generator
    • ? roll
    • ? deal
    • … range
    • … one range
    • ⍮ pair
    • ⍮ singleton
  • dictionary functions
    • ‥ from keys and values
    • ߹ key-value pair
    • ‥ from inverted table
    • ߹ from pairs
    • ⍉ inverted table
    • ↓ key-value pairs
    • ⊃ keys
    • ⊇ values
  • manipulation functions
    • ↑ take
    • ↓ drop
    • ↑ mix
    • ↓ major cells (split is ⊂⍤1)
    • ⊂ enclose
    • ⊆ nest
    • ⊂ partitioned enclose
    • ⊆ partition
    • ⫇ group
    • ⍋ grade up
    • ⍒ grade down
    • ⍋ sort by up
    • ⍒ sort by down
    • ⊴ sort up
    • ⊵ sort down
    • ⍸ where
    • ∊ enlist
    • ⌿ replicate
    • , ravel
    • ⍪ join
    • ⍪ catenate
    • ⍴ reshape
    • ϼ rerank (generalized version of promote/demote: introduce leading length-1 axes or combine leading axes)
    • ⊖ reverse
    • ⊖ rotate
    • ⍉ transpose
    • ⍉ reorder axes
    • ∧ promote (introduce leading axis)
    • ∨ demote (combine two leading axes)
    • , laminate
  • lookup functions
    • ⊃ first
    • ⊇ last
    • > first cell
    • ≥ last cell
    • ⊇ from
    • ⌷ index
    • ⊃ pick
  • misc functions
    • ⊢/⊣ same
    • ⊢ right
    • ⊣ left
    • ⍎ execute
    • ⍕ format
    • ↗ raise
    • ⇂ minimal (TAO minimum)
    • ↾ maximal (TAO maximum)
  • operators
    • / reduce (left-to-right)
    • / fold (seeded reduce)
    • \ reduce back (right-to-left)
    • \ fold back
    • ↟ on prefixes
    • ↡ on suffixes
    • ↡ on infixes
    • ↟ on outfixes
    • ¨ each
    • ᐵ each-left
    • ᑈ each-right
    • ᑣ boxed (⊂⍤)
    • ᑒ on contents (⍥⊃)
    • ⍣ repeat
    • ⍣ until
    • ∙ inner product
    • ∙ alternant?
    • ⊞ table
    • ⍤ at rank
    • ◡ on cells (⍤¯1)
    • ◠ on scalars (⍤0)
    • ᓗ cells-left (⍤¯1‿∞)
    • ᓚ cells-right (⍤∞‿¯1)
    • ⍥ at depth
    • ⌓ on simple scalars (⍥0)
    • @ at
    • ⌸ key
    • ⌸ key with vocabulary
    • ⍁ diagonals?
    • ⌺ stencil
    • ⁖ valences (call left if monad and right if dyad)
    • ⍢ strucutral under
    • ∵ bitwise
    • ⎊ catch
  • combinators
    • ⍨ constant
    • ⍨ commute
    • ⍨ duplicate
    • ∘ bind argument
    • ∘ after
    • ⍛ default argument (uses operand if called monadically, and argument if called dyadically)
    • ⍛ before (not a hook!)
    • ⊸ left hook
    • ⟜ right hook
    • ⍤ atop
    • ⍥ over
    • ⸚ mirror (_{(⍵ ⍹⍹ ⍺)⍶⍶(⍺ ⍹⍹ ⍵)}_)
    • «/» fork
    • ⇾ left fork (_{(⍺ ⍶⍶ ⍵) ⍹⍹ ⍵}_)
    • ⇽ right fork (_{⍺ ⍶⍶ (⍺ ⍹⍹ ⍵)}_)
    • ⫤ ident (adverb returning the operand)
    • ⫣ lev (conjunction returning the left operand)
    • ⊩ dex (conjunction returning the right operand)
• system names (quad names)
  • support for system names in parsing and interpreting
  • system nilads
    • ⎕u (constant) the uppercase alphabet
    • ⎕l (constant) the lowercase alphabet
    • ⎕d (constant) the digits
    • ⎕ts current timestamp (year, month, day, hour, minute, second, millisecond)
    • ⎕unix current Unix timestamp
    • ⎕io (constant) 1
    • ⎕ct (constant) 1⏨¯14
    • ⎕seed (set only) seed the random number generator
    • ⎕math math functions
    • ⎕systemInfo system information
  • system functions
    • ⎕File read/write files
    • ⎕DateTime (or ⎕DT maybe?) convert between time formats
    • ⎕HTTP http requests
    • ⎕CSV convert from/to CSV
    • ⎕JSON convert from/to JSON
    • ⎕Unicode convert between unicode representations
    • ⎕Exists does a variable exist?
    • ⎕Repr convert an array to a representation that can be read with Execute
    • ⎕Assert assertions
    • ⎕Delay sleep for n seconds
    • ⎕Import import a module
    • ⎕Type type of a scalar
  • system adverbs
    • ⎕_BinFile read/write binary files, with format chosen from the operand
  • system conjunctions