{"id":19666628,"url":"https://github.com/xaionaro-go/rpn","last_synced_at":"2026-06-25T08:31:28.597Z","repository":{"id":71636440,"uuid":"307480243","full_name":"xaionaro-go/rpn","owner":"xaionaro-go","description":"Reverse Polish Notation for Go 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report](https://goreportcard.com/badge/github.com/xaionaro-go/rpn)](https://goreportcard.com/report/github.com/xaionaro-go/rpn)\n[![Build Status](https://travis-ci.org/xaionaro-go/rpn.svg?branch=master)](https://travis-ci.org/xaionaro-go/rpn)\n[![Coverage Status](https://coveralls.io/repos/github/xaionaro-go/rpn/badge.svg?branch=master)](https://coveralls.io/github/xaionaro-go/rpn?branch=master)\n\u003cp xmlns:dct=\"http://purl.org/dc/terms/\" xmlns:vcard=\"http://www.w3.org/2001/vcard-rdf/3.0#\"\u003e\n  \u003ca rel=\"license\"\n     href=\"http://creativecommons.org/publicdomain/zero/1.0/\"\u003e\n    \u003cimg src=\"http://i.creativecommons.org/p/zero/1.0/88x31.png\" style=\"border-style: none;\" alt=\"CC0\" /\u003e\n  \u003c/a\u003e\n  \u003cbr /\u003e\n  To the extent possible under law,\n  \u003ca rel=\"dct:publisher\"\n     href=\"https://github.com/xaionaro-go/rpn\"\u003e\n    \u003cspan property=\"dct:title\"\u003eDmitrii Okunev\u003c/span\u003e\u003c/a\u003e\n  has waived all copyright and related or neighboring rights to\n  \u003cspan property=\"dct:title\"\u003eReverse Polish Notation for Go\u003c/span\u003e.\nThis work is published from:\n\u003cspan property=\"vcard:Country\" datatype=\"dct:ISO3166\"\n      content=\"IE\" about=\"https://github.com/xaionaro-go/rpn\"\u003e\n  Ireland\u003c/span\u003e.\n\u003c/p\u003e\n\n# About\n\n`github.com/xaionaro-go/rpn` is an implementation of [Reverse Polish Notation](https://en.wikipedia.org/wiki/Reverse_Polish_notation).\nThe implementation is focused on fast evaluation (but slow parsing).\n\n# Quick start\n\n```go\npackage main\n\nimport (\n\t\"fmt\"\n\n\t\"github.com/xaionaro-go/rpn\"\n\t\"github.com/xaionaro-go/rpn/types\"\n)\n\ntype variables struct {\n\tX float64\n}\n\nfunc (r *variables) Resolve(sym string) (types.ValueLoader, error) {\n\tswitch sym {\n\tcase \"x\":\n\t\treturn types.FuncValue(func(any) float64 {\n\t\t\treturn r.X\n\t\t}), nil\n\t}\n\treturn nil, fmt.Errorf(\"symbol '%s' not found\", sym)\n}\n\nfunc main() {\n\tvars := \u0026variables{}\n\texpr, err := rpn.Parse(\"x 2 *\", vars)\n\tif err != nil {\n\t\tpanic(err)\n\t}\n\n\tvars.X = 1\n\t_, _ = fmt.Println(expr.Eval(nil))\n\n\tvars.X = 3\n\t_, _ = fmt.Println(expr.Eval(nil))\n}\n```\nThe output is:\n```\n2\n6\n```\n\n# Benchmark\n\nThere are 5 approaches implemented (`callslice`, `calltree`, `exprtree`, `compile` and `tokenslice`):\n\n```\ngoos: linux\ngoarch: amd64\npkg: github.com/xaionaro-go/rpn/tests\ncpu: AMD Ryzen 9 5900X 12-Core Processor            \nBenchmarkExpr_Eval/cache_true/3_constant_values/callslice-24         \t338823202\t        3.526 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_constant_values/calltree-24          \t342666187\t        3.501 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_constant_values/exprtree-24          \t337961120\t        3.626 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_constant_values/compile-24           \t342394530\t        3.487 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_constant_values/tokenslice-24        \t334232605\t        3.556 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_constant_values/default-24           \t344161088\t        3.481 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_variables/exprtree-24                \t328156056\t        3.539 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_variables/compile-24                 \t339983692\t        3.574 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_variables/tokenslice-24              \t339623660\t        3.486 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_variables/default-24                 \t346571980\t        3.560 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_variables/callslice-24               \t342680188\t        3.477 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/3_variables/calltree-24                \t320866833\t        3.574 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10_variables/tokenslice-24             \t341432474\t        3.493 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10_variables/default-24                \t329531038\t        3.569 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10_variables/callslice-24              \t341855184\t        3.537 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10_variables/calltree-24               \t343456281\t        3.494 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10_variables/exprtree-24               \t334949788\t        3.648 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10_variables/compile-24                \t343865816\t        3.488 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/100_variables/calltree-24              \t339102571\t        3.527 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/100_variables/exprtree-24              \t337756276\t        3.527 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/100_variables/compile-24               \t333295226\t        3.548 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/100_variables/tokenslice-24            \t346515900\t        3.511 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/100_variables/default-24               \t341047189\t        3.482 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/100_variables/callslice-24             \t340326940\t        3.564 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/1000_variables/callslice-24            \t341819227\t        3.489 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/1000_variables/calltree-24             \t345551792\t        3.552 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/1000_variables/exprtree-24             \t344173688\t        3.509 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/1000_variables/compile-24              \t339122401\t        3.569 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/1000_variables/tokenslice-24           \t340029790\t        3.527 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/1000_variables/default-24              \t338550138\t        3.509 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10000_variables/exprtree-24            \t340234605\t        3.544 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10000_variables/compile-24             \t344656420\t        3.476 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10000_variables/tokenslice-24          \t334536746\t        3.602 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10000_variables/default-24             \t338500122\t        3.505 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10000_variables/callslice-24           \t337411789\t        3.648 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_true/10000_variables/calltree-24            \t341668298\t        3.593 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_constant_values/callslice-24        \t141478860\t        8.563 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_constant_values/calltree-24         \t259093815\t        4.681 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_constant_values/exprtree-24         \t82469947\t       14.70 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_constant_values/compile-24          \t100000000\t       11.25 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_constant_values/tokenslice-24       \t71216802\t       17.23 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_constant_values/default-24          \t245641957\t        4.803 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_variables/callslice-24              \t82744274\t       14.53 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_variables/calltree-24               \t100000000\t       10.85 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_variables/exprtree-24               \t52943655\t       21.73 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_variables/compile-24                \t59577981\t       20.51 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_variables/tokenslice-24             \t54594726\t       22.58 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/3_variables/default-24                \t100000000\t       10.83 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10_variables/compile-24               \t22511331\t       54.22 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10_variables/tokenslice-24            \t17895859\t       67.43 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10_variables/default-24               \t33715436\t       34.74 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10_variables/callslice-24             \t25407411\t       46.86 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10_variables/calltree-24              \t31303549\t       36.59 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10_variables/exprtree-24              \t17891308\t       68.98 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/100_variables/default-24              \t2765348\t      448.3 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/100_variables/callslice-24            \t2627880\t      459.6 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/100_variables/calltree-24             \t2836452\t      429.9 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/100_variables/exprtree-24             \t1637896\t      724.5 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/100_variables/compile-24              \t1581406\t      754.3 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/100_variables/tokenslice-24           \t1773808\t      671.8 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/1000_variables/compile-24             \t 156962\t     7794 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/1000_variables/tokenslice-24          \t 185878\t     6509 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/1000_variables/default-24             \t 246588\t     4806 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/1000_variables/callslice-24           \t 244425\t     4858 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/1000_variables/calltree-24            \t 276615\t     4335 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/1000_variables/exprtree-24            \t 170758\t     6955 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10000_variables/callslice-24          \t  22401\t    52229 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10000_variables/calltree-24           \t  26130\t    46719 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10000_variables/exprtree-24           \t  15268\t    78926 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10000_variables/compile-24            \t  15032\t    81232 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10000_variables/tokenslice-24         \t  18117\t    66644 ns/op\t      0 B/op\t      0 allocs/op\nBenchmarkExpr_Eval/cache_false/10000_variables/default-24            \t  25033\t    46930 ns/op\t      0 B/op\t      0 allocs/op\n```\n\nThe default approach for small expressions is `calltree`, and\nfor larger expression is `callslice`, so if you will import\n`github.com/xaionaro-go/rpn` then if you will use them.\n\n\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fxaionaro-go%2Frpn","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fxaionaro-go%2Frpn","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fxaionaro-go%2Frpn/lists"}