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# Jonathan Harrop jdh30

Created May 9, 2019
Hans Boehm's binary trees benchmark in F#
View binarytrees.fs
 [] type Tree = Empty | Node of Tree * Tree let rec make depth = if depth=0 then Empty else Node(make (depth-1), make (depth-1)) let rec check = function | Empty -> 1 | Node(l, r) -> 1 + check l + check r
Created May 9, 2019
Hans Boehm's binary trees benchmark in C++ using the default new+delete
View binarytrees.cpp
 #include #include #include struct Node { Node *l, *r; Node() : l(0), r(0) {} Node(Node* l2, Node* r2) : l(l2), r(r2) {} ~Node() { delete l; delete r; } int check() const {
Created Apr 28, 2019
McCarthy's definition of LISP 1.5 in itself
View gist:438afaed15d3bb7af3bfaedf54c4852b
 ; 20LOC to define a useful language ; However, no strings, IO, closure semantics or GC. apply[fn;x;a] = [atom[fn] -> [eq[fn;CAR] -> caar[x]; eq[fn;CDR] -> cdar[x]; eq[fn;CONS] -> cons[car[x];cadr[x]]; eq[fn;ATOM] -> atom[car[x]]; eq[fn;EQ] -> eq[car[x];cadr[x]]; T -> apply[eval[fn;a];x;a]];
Created Feb 28, 2019
Memory management benchmark - shedding Eddys
View Eddy.fs
 (* This benchmark maintains an array of roots and randomly either pushes onto them and relinks them or empties them. If I designed it correctly then this should rapidly create unreachable subgraphs, some of which are cyclic. This is a torture test for any kind of reference counting. *) type Vertex = { mutable Dst: Vertex }
Last active Feb 28, 2019
A program for which prompt collection is practically impossible
View promptness.fs
 (* The resizable array xs is required for the first half of the execution of this "test" function but not the last half. Collecting xs as early as possible would mean collecting it halfway through the execution of "test" but this is practically impossible. Doing so in general is equivalent to solving the halting problem. *) let next n = 6364136223846793005UL*n + 1442695040888963407UL
Last active Jun 11, 2021
Simple JSON parser written in F# using active patterns
View JsonParser.fs
 type Json = | Null | Bool of bool | Number of float | String of string | Array of Json list | Object of (string * Json) list type Bracket = Open | Close
Last active Sep 17, 2019
Ray tracer in Julia
View ray.jl
 // Translated from the Ray Tracer Language Comparison // http://www.ffconsultancy.com/languages/ray_tracer/benchmark.html import Printf struct Hit l ::Float64 d ::Array{Float64, 1} end
Last active Oct 13, 2018
Fast inverse sqrt in F#
View Q_rsqrt.fs
 // The famous fast inverse square root approximation from // Quake ported to F#. // Note: this algorithm is not fast on modern computers // and this implementation of it is extremely inefficient: // for educational purposes only! open System let isqrt y = let x2 = y * 0.5f
Created Mar 12, 2018
A parser definition in F# written in the style of a Camlp4 parser
View Camlp4LikeParser.fs
 let reint = R(Regex "[0-9]+") let relident = R(Regex "[a-z][a-zA-Z0-9]*") let grammar : Grammar = [ Expr, [ [ S"if"; C Expr; S"then"; C Expr; S"else"; C Expr ], fun [E p; E t; E f] -> E(If(p, t, f)) [ C Expr; S"<="; C Expr ], fun [E e1; E e2] -> E(BinOp(e1, Le, e2)) [ C Expr; S"+"; C Expr ], fun [E e1; E e2] -> E(BinOp(e1, Add, e2)) [ C Expr; S"-"; C Expr ], fun [E e1; E e2] -> E(BinOp(e1, Sub, e2))
Created Mar 4, 2018
Port of an camlp4-based inline parser to vanilla ML
View SimpleParser1.fs
 // See: https://gist.github.com/jdh30/6130c615b5945fd57fc0ea74fcb87e05 open System.Text.RegularExpressions type BinOp = Add | Sub | Le type expr = | Int of int | Var of string | BinOp of expr * BinOp * expr