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Add flat combinator

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This commit is contained in:
Scott Richmond 2023-05-16 18:29:22 -04:00
parent cbd78ce7f7
commit 52abde501a
1 changed files with 26 additions and 16 deletions
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42
src/ludus/parser-new.clj
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@ -13,7 +13,7 @@
(defn pass? [{status :status}] (contains? passing status))
(defn fail? [{status :status}] (conatins? failing status))
(defn fail? [{status :status}] (contains? failing status))
(defn data [{d :data}] d)
@ -59,7 +59,7 @@
rem-ts (remaining result)
rem-ps (rest ps)]
(cond
(pass? result)
(pass? result) ;result
{:status :ok :type name :data [result] :token (first tokens) :remaining rem-ts}
(= :err (:status result))
@ -86,9 +86,9 @@
(:ok :quiet :group)
(loop [ps (rest parsers)
results (case (:status first-result)
:ok [first-result]
:quiet []
:group (:data first-result))
:ok [first-result]
:quiet []
:group (:data first-result))
ts (remaining first-result)]
(let [result (apply-parser (first ps) ts)
res-rem (remaining result)]
@ -164,13 +164,13 @@
:token (first tokens)
:remaining (remaining rest-result)})
:quiet
(let [rest-result (apply-parser rest-parser (remaining first-result))]
{:status :quiet
:type name
:data []
:token (first tokens)
:remaining (remaining rest-result)})
:quiet
(let [rest-result (apply-parser rest-parser (remaining first-result))]
{:status :quiet
:type name
:data []
:token (first tokens)
:remaining (remaining rest-result)})
(:err :none) first-result)))}))
@ -185,6 +185,14 @@
{:status :group :type name :data [] :token (first tokens) :remaining tokens}
)))}))
(defn flat
([parser] (flat (pname parser) parser))
([name parser]
{:name (kw+str name "-flat")
:rule (fn flat-fn [tokens]
(let [result (apply-parser parser tokens)]
(if (pass? result) (first (:data result)) result)))}))
(comment
"
If I'm not mistaken, the Ludus grammer requires *no* lookahead, the first token in an expression tells you what kind of expression it is:
@ -219,7 +227,7 @@
(declare expression)
(def literal (choice :literal [:nil :true :false :number :string]))
(def literal (flat (choice :literal [:nil :true :false :number :string])))
(def separator (choice :separator [:comma :newline]))
@ -257,7 +265,7 @@
(def splat (order :splat [(quiet :splat) :word]))
(def list-term (choice :list-term [splat expression]))
(def list-term (flat (choice :list-term [splat expression])))
(def list-entry (order :list-entry [(quiet (one+ separator)) list-term]))
@ -285,7 +293,7 @@
(def importt (order :import [(quiet :import) :string (quiet :as) :word]))
(def toplevel (choice :toplevel [importt expression]))
(def toplevel (flat (choice :toplevel [importt expression])))
(def script-line (order :script-line [(quiet terminator) toplevel]))
@ -293,7 +301,9 @@
(def eg (:tokens (scan/scan
""
"1
2
3"
)))
eg