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| author | Case Duckworth | 2024-03-19 22:13:44 -0500 |
|---|---|---|
| committer | Case Duckworth | 2024-03-19 22:13:44 -0500 |
| commit | 9c5643d5f78e4228d47e293b421d7f388d47945f (patch) | |
| tree | 3925d137d7820622b38f183ad259475ff48b39e5 /eval.lua | |
| parent | Add QUOTE, QUASIQUOTE, UNQUOTE reading and generalize (diff) | |
| download | lam-9c5643d5f78e4228d47e293b421d7f388d47945f.tar.gz lam-9c5643d5f78e4228d47e293b421d7f388d47945f.zip | |
A new start!
Diffstat (limited to 'eval.lua')
| -rw-r--r-- | eval.lua | 39 |
1 files changed, 6 insertions, 33 deletions
| diff --git a/eval.lua b/eval.lua index 5e897e2..e926bc4 100644 --- a/eval.lua +++ b/eval.lua | |||
| @@ -1,6 +1,7 @@ | |||
| 1 | --- lam.eval | 1 | --- lam.eval |
| 2 | 2 | ||
| 3 | local eval = {} | 3 | local eval = {} |
| 4 | local base = require "base" | ||
| 4 | local type = require "type" | 5 | local type = require "type" |
| 5 | local isNull, isList, isa, List, Cons = | 6 | local isNull, isList, isa, List, Cons = |
| 6 | type.isNull, type.isList, type.isa, type.List, type.Cons | 7 | type.isNull, type.isList, type.isa, type.List, type.Cons |
| @@ -30,6 +31,7 @@ function eval.Proc (params, body, env) | |||
| 30 | inner[p.car] = a.car | 31 | inner[p.car] = a.car |
| 31 | p, a = p.cdr, a.cdr | 32 | p, a = p.cdr, a.cdr |
| 32 | end | 33 | end |
| 34 | pp.pp(self.body) | ||
| 33 | return eval.eval( | 35 | return eval.eval( |
| 34 | self.body, | 36 | self.body, |
| 35 | eval.Env(inner, self.env)) | 37 | eval.Env(inner, self.env)) |
| @@ -38,37 +40,8 @@ function eval.Proc (params, body, env) | |||
| 38 | return setmetatable(v, mt) | 40 | return setmetatable(v, mt) |
| 39 | end | 41 | end |
| 40 | 42 | ||
| 41 | local global = { | ||
| 42 | begin = | ||
| 43 | function (r) | ||
| 44 | local r = r | ||
| 45 | while not isNull(r.cdr) do | ||
| 46 | r = r.cdr | ||
| 47 | end | ||
| 48 | return r.car | ||
| 49 | end, | ||
| 50 | ["+"] = | ||
| 51 | function (r) | ||
| 52 | local r, a = r, 0 | ||
| 53 | while r.cdr do | ||
| 54 | r, a = r.cdr, a + r.car | ||
| 55 | end | ||
| 56 | return a | ||
| 57 | end, | ||
| 58 | ["-"] = | ||
| 59 | function (r) | ||
| 60 | if isNull(r) then return -1 end | ||
| 61 | if isNull(r.cdr) then return (- r.car) end | ||
| 62 | local r, a = r.cdr, r.car | ||
| 63 | while r.cdr do | ||
| 64 | r, a = r.cdr, a - r.car | ||
| 65 | end | ||
| 66 | return a | ||
| 67 | end, | ||
| 68 | } | ||
| 69 | |||
| 70 | function eval.eval (x, env) | 43 | function eval.eval (x, env) |
| 71 | env = env or global | 44 | env = env or base.env |
| 72 | if isa(x, "Symbol") then | 45 | if isa(x, "Symbol") then |
| 73 | return env[x] | 46 | return env[x] |
| 74 | elseif not isList(x) then | 47 | elseif not isList(x) then |
| @@ -77,13 +50,13 @@ function eval.eval (x, env) | |||
| 77 | local op, args = x.car, x.cdr | 50 | local op, args = x.car, x.cdr |
| 78 | if op == "quote" then | 51 | if op == "quote" then |
| 79 | return args.car | 52 | return args.car |
| 80 | elseif op == "define" then | 53 | elseif op == "define" or op == "def" then |
| 81 | env[args.car] = eval.eval(args.cdr.car, env) | 54 | env[args.car] = eval.eval(args.cdr.car, env) |
| 82 | return nil | 55 | return nil |
| 83 | elseif op == "lambda" then | 56 | elseif op == "lambda" or op == "lam" then |
| 84 | return eval.Proc( | 57 | return eval.Proc( |
| 85 | args.car, | 58 | args.car, |
| 86 | Cons("begin", args.cdr), | 59 | Cons("begin", args.cdr), -- i don't like this |
| 87 | env) | 60 | env) |
| 88 | elseif op == "if" then | 61 | elseif op == "if" then |
| 89 | assert(not isNull(args.cdr), "Malformed 'if'") | 62 | assert(not isNull(args.cdr), "Malformed 'if'") |