Finally get error handling right?
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@ -25,13 +25,24 @@
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(defn- token-type [parser]
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(::token/type (current parser)))
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(defn- node-type [parser]
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(get-in parser [::ast ::ast/type]))
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;; some forward declarations
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(declare parse-expr)
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(declare parse-word)
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;; handle some errors
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(def sync-on #{
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::token/newline
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::token/semicolon
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::token/comma
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::token/rparen
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::token/rbracket
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::token/rbrace
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})
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(defn- sync [parser message origin end]
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(println "Synching on " (current parser))
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(let [poison {
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::ast/type ::ast/poison
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:message message
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@ -45,17 +56,48 @@
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(defn- poisoned? [parser]
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(= ::ast/poison (get-in parser [::ast ::ast/type])))
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(defn- panic [parser message sync-on]
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(defn- panic
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([parser message] (panic parser message sync-on))
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([parser message sync-on]
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(println "PANIC!!! in the parser")
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(let [origin (current parser)]
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(loop [parser parser]
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(loop [parser (advance parser)]
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(let [
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curr (current parser)
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type (::token/type curr)
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]
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(if (or (= ::token/eof type) (contains? sync-on type))
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(sync parser message origin curr)
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(recur (advance parser)))))))
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(recur (advance parser))))))))
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;; some helper functions
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(defn- expect [tokens message parser]
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(let [curr (current parser)
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tokens (if (set? tokens) tokens #{tokens})
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type (::token/type curr)]
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(if (contains? tokens type)
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(advance parser)
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(-> parser
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(advance)
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(panic message tokens)))))
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(defn- accept [tokens parser]
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(let [curr (current parser)
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tokens (if (set? tokens) tokens #{tokens})
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type (::token/type curr)]
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(if (contains? tokens type)
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(advance parser)
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parser)))
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(defn- accept-many [tokens parser]
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(let [tokens (if (set? tokens) tokens #{tokens})]
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(loop [parser parser]
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(let [
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curr (current parser)
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type (::token/type curr)]
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(if (contains? tokens type)
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(recur (advance parser))
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parser)))))
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;; various parsing functions
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(defn- parse-atom [parser]
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@ -89,31 +131,37 @@
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(conj members member)))
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(defn- parse-tuple [parser]
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(loop [parser (advance parser)
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(loop [
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parser (accept-many #{::token/newline ::token/comma} (advance parser))
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members []
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current_member nil]
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(let [curr (current parser)]
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(case (::token/type curr)
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current_member nil
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]
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(let [
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curr (current parser)
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]
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(case (token-type parser)
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::token/rparen (let [ms (add-member members current_member)]
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(assoc (advance parser) ::ast
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{::ast/type ::ast/tuple
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:length (count ms)
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:members ms}))
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(::token/comma ::token/newline) (recur (advance parser) (add-member members current_member) nil)
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(::token/comma ::token/newline)
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(recur
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(accept-many #{::token/comma ::token/newline} parser)
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(add-member members current_member) nil)
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(::token/rbrace ::token/rbracket)
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(panic parser (str "Mismatched enclosure in tuple: " (::token/lexeme curr)))
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(let [parsed (parse-expr parser)]
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(if (poisoned? parsed)
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(let [
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panicked
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(panic parser (get-in parsed [::ast :message]) #{::token/rparen})
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]
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(recur panicked members (::ast panicked))
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)
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(recur parsed members (::ast parsed))
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)
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)
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))))
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)
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)
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)
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)
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(defn- parse-list [parser]
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(loop [parser (advance parser)
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@ -240,29 +288,6 @@
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(assoc ::ast {::ast/type ::ast/poison :message "Expected pattern"}))
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)))
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(defn- expect [token message parser]
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(let [curr (current parser)
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type (::token/type curr)]
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(if (= type token)
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(advance parser)
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(-> parser
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(advance)
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(panic message #{token})))))
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(defn- accept [token parser]
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(let [curr (current parser)
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type (::token/type curr)]
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(if (= type token)
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(advance parser)
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parser)))
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(defn- accept-many [token parser]
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(loop [curr (current parser)]
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(let [type (::token/type curr)]
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(if (= type token)
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(recur (advance parser))
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parser))))
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(defn- parse-let-expr [parser pattern]
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(let [expr (parse-expr parser)]
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(assoc expr ::ast {::ast/type ::ast/let
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@ -364,15 +389,14 @@
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(do
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(def pp pp/pprint)
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(def source "(12, 43, arf@)
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")
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(def source "(1, 2, (},; 4, 123^)")
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(def lexed (scanner/scan source))
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(def tokens (:tokens lexed))
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(def p (parser tokens))
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(-> p
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(parse-script)
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(::ast)
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(::errors)
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(pp)
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)
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)
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