55 lines
1.0 KiB
Plaintext
55 lines
1.0 KiB
Plaintext
|
# A tree walk interpreter for ludus
|
||
|
|
|
||
|
|
(var interpret nil)
|
||
|
|
|
||
|
|
(defn- iff [ast ctx]
|
||
|
|
(def [condition then else] (ast :data))
|
||
|
|
(if (interpret condition ctx)
|
||
|
|
(interpret then ctx)
|
||
|
|
(interpret else ctx)))
|
||
|
|
|
||
|
|
(defn- script [ast ctx]
|
||
|
|
(print "interpreting script")
|
||
|
|
(def lines (ast :data))
|
||
|
|
(var result nil)
|
||
|
|
(each line lines
|
||
|
|
(print "interpreting script line")
|
||
|
|
(set result (interpret line ctx)))
|
||
|
|
result)
|
||
|
|
|
||
|
|
(defn- interpret* [ast ctx]
|
||
|
|
(print "interpreting ast node " (ast :type))
|
||
|
|
(case (ast :type)
|
||
|
|
:nil nil
|
||
|
|
:number (ast :data)
|
||
|
|
:bool (ast :data)
|
||
|
|
:string (ast :data)
|
||
|
|
:keyword (ast :data)
|
||
|
|
:if (iff ast ctx)
|
||
|
|
:script (script ast ctx)))
|
||
|
|
|
||
|
|
(set interpret interpret*)
|
||
|
|
|
||
|
|
# repl
|
||
|
|
(try (os/cd "janet") ([_] nil))
|
||
|
|
(import ./scanner :as s)
|
||
|
|
(import ./parser :as p)
|
||
|
|
(import ./validate :as v)
|
||
|
|
|
||
|
|
(var source nil)
|
||
|
|
|
||
|
|
(defn run []
|
||
|
|
(def scanned (s/scan source))
|
||
|
|
(def parsed (p/parse scanned))
|
||
|
|
(def validated (v/valid parsed))
|
||
|
|
(pp parsed)
|
||
|
|
(interpret (parsed :ast) @{}))
|
||
|
|
|
||
|
|
|
||
|
|
(do
|
||
|
|
(set source `
|
||
|
|
if false then :bar else :baz
|
||
|
|
`)
|
||
|
|
(run)
|
||
|
|
)
|