diff options
Diffstat (limited to 'src/cljcc')
| -rw-r--r-- | src/cljcc/parser.clj | 48 |
1 files changed, 35 insertions, 13 deletions
diff --git a/src/cljcc/parser.clj b/src/cljcc/parser.clj index 0feb388..f1da784 100644 --- a/src/cljcc/parser.clj +++ b/src/cljcc/parser.clj @@ -3,24 +3,44 @@ [cljcc.lexer :as l] [clojure.pprint :as pp])) -(defn- expect [expected-kind [token & rst]] - (if (= expected-kind (:kind token)) +(defn- expect [kind [token & rst]] + (if (= kind (:kind token)) [token rst] - (throw (ex-info "Parser Error." {:expected expected-kind + (throw (ex-info "Parser Error." {:expected kind :actual (:kind token)})))) -(defn- parse-exp [tokens] - (let [[t rst] (expect :number tokens)] - [{:type :exp - :value {:type :constant-exp - :value (:literal t)}} rst])) +(defn- expect-in [kinds [{kind :kind :as token} & rst]] + (if (contains? kinds kind) + [token rst] + (throw (ex-info "Parser Error." {:expected kinds + :actual token})))) + +(defn- parse-exp [[{kind :kind :as token} :as tokens]] + (cond + (= kind :number) [{:type :exp + :exp-type :constant-exp + :value (:literal token)} + (rest tokens)] + (contains? + #{:complement :hyphen} kind) (let [operator kind + [e rst] (parse-exp (rest tokens))] + [{:type :exp + :exp-type :unary-exp + :unary-operator operator + :value e} + rst]) + (= kind :left-paren) (let [[e rst] (parse-exp (rest tokens)) + [_ rst] (expect :right-paren rst)] + [e rst]) + :else (throw (ex-info "Parser Error." {:expected "number, (, -, ~" + :actual token})))) (defn- parse-return-statement [tokens] (let [[_ rst] (expect :kw-return tokens) - [constant-node rst] (parse-exp rst)] + [exp-node rst] (parse-exp rst)] [{:type :statement :statement-type :return - :value constant-node} + :value exp-node} rst])) (defn- parse-statement @@ -66,14 +86,16 @@ (comment - (parse "int main(void) {return 2;}") - (pp/pprint (parse (l/lex " int main(void) { - return 2; + return -(~~~(2)); }"))) (pp/pprint + (l/lex + "int main(void) {return (((2)))}")) + + (pp/pprint (l/lex " int main(void) { return 2; |