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Improve parse-script; start work on let and pattern

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This commit is contained in:
Scott Richmond 2022-02-21 15:38:47 -05:00
parent 8ec432c7a0
commit f96ec45d1b
1 changed files with 45 additions and 38 deletions
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83
src/ludus/parser.clj
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@ -3,7 +3,8 @@
[ludus.token :as token]
[ludus.scanner :as scanner]
[ludus.ast :as ast]
[clojure.pprint :as pp]))
[clojure.pprint :as pp]
[clojure.set :as s]))
;; a parser map and some functions to work with them
(defn- parser [tokens]
@ -232,7 +233,9 @@
})))
(::token/semicolon ::token/newline)
(recur (advance parser) (add-member exprs current_expr) nil)
(recur
(accept-many #{::token/newline ::token/semicolon} parser)
(add-member exprs current_expr) nil)
(::token/rbracket ::token/rparen)
(panic parser (str "Mismatched enclosure in block: " (::token/lexeme curr)))
@ -245,37 +248,34 @@
(if current_expr
(panic parser "Expected end of expression" #{::token/semicolon ::token/newline})
(parse-expr parser))]
(recur parsed exprs (::ast parsed))
)
)
)
))
(recur parsed exprs (::ast parsed)))))))
(defn- parse-script [parser]
(loop [parser parser
(defn- parse-script* [parser]
(loop [
parser (accept-many #{::token/newline ::token/semicolon} parser)
exprs []
current_expr nil]
(if (at-end? parser)
(assoc parser ::ast
{::ast/type ::ast/script :exprs (add-member exprs current_expr)})
(case (::token/type (current parser))
::token/eof (assoc parser ::ast
{::ast/type ::ast/script :exprs (add-member exprs current_expr)})
current_expr nil
]
(let [curr (current parser)]
(case (token-type parser)
::token/eof (let [es (add-member exprs current_expr)]
(if (empty? es)
(panic parser "Scripts must have at least one expression")
(assoc parser ::ast {::ast/type ::ast/script :exprs es})))
(::token/semicolon ::token/newline)
(recur (advance parser) (add-member exprs current_expr) nil)
(recur
(accept-many #{::token/semicolon ::token/newline} parser)
(add-member exprs current_expr)
nil)
(if current_expr
(if (poisoned? current_expr)
(panic parser (:message current_expr) #{::token/newline ::token/semicolon})
(let [synced (panic parser "Expected end of expression" #{::token/newline ::token/semicolon})]
(recur synced exprs (::ast synced))
))
(let [parsed (parse-expr parser)]
(recur parsed exprs (::ast parsed))
))
))))
(let [parsed
(if current_expr
(panic parser "Expected end of expression" #{::token/semicolon ::token/newline})
(parse-expr parser)
)
]
(recur parsed exprs (::ast parsed)))))))
(defn- parse-synthetic [parser]
(loop [parser parser
@ -304,6 +304,8 @@
(advance)
(assoc ::ast {::ast/type ::ast/word :word (::token/lexeme curr)}))))
(def sync-pattern (s/union sync-on #{::token/equals ::token/rarrow}))
(defn- parse-pattern [parser]
(let [curr (current parser)
type (::token/type curr)]
@ -312,9 +314,11 @@
(::token/number ::token/string ::token/keyword) (parse-atom parser)
(-> parser
(advance)
(assoc ::ast {::ast/type ::ast/poison :message "Expected pattern"}))
::token/error
(panic parser (:message (current parser)) sync-pattern)
(panic parser "Expected pattern" sync-pattern)
)))
(defn- parse-let-expr [parser pattern]
@ -330,9 +334,7 @@
(defn- parse-let [parser]
(let [pattern (parse-pattern (advance parser))]
(if (poisoned? pattern)
(panic parser (get-in pattern [::ast :message]) #{::token/newline ::token/semicolon})
(parse-assignment pattern))))
(parse-assignment pattern)))
(defn- parse-if [parser]
(let [
@ -401,15 +403,20 @@
(do
(def pp pp/pprint)
(def source "{ 1; 2; \"foo
}")
(def source "let foo^ = bar")
(def lexed (scanner/scan source))
(def tokens (:tokens lexed))
(def p (parser tokens))
(println "")
(println "")
(println "******************************************************")
(println "")
(println "*** *** NEW PARSE *** ***")
(-> p
(parse-script)
(::errors)
(parse-script*)
(::ast)
(pp)
)
)