1 files changed, 37 insertions, 0 deletions

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+--- lam.base --- base environment
+
+local base = {}
+local type = require "type"
+local isNull = type.isNull
+
+base.env = {
+        begin =
+                function (r)
+                        local r = r
+                        while not isNull(r.cdr) do
+                                r = r.cdr
+                        end
+                        return r.car
+                end,
+        ["+"] =
+                function (r)
+                        local r, a = r, 0
+                        while r.cdr do
+                                r, a = r.cdr, a + r.car
+                        end
+                        return a
+                end,
+        ["-"] =
+                function (r)
+                        if isNull(r) then return -1 end
+                        if isNull(r.cdr) then return (- r.car) end
+                        local r, a = r.cdr, r.car
+                        while r.cdr do
+                                r, a = r.cdr, a - r.car
+                        end
+                        return a
+                end,
+}
+
+---
+return base