Limited monomorphic-only Damas-Hindley-Milner implemented in types
This commit is contained in:
Nathan Braswell
95
types.kp
95
types.kp
@@ -7,54 +7,72 @@
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(recurse dict key (+ i 1))))))
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(lambda (dict key) (lookup-helper dict key 0)))
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with_type (lambda (exp typ) [exp typ])
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get_exp (lambda (et) (idx et 0))
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get_typ (lambda (et) (idx et 1))
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get_ret_typ (lambda (f_typ) (idx f_typ 1))
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get_params_typs (lambda (f_typ) (idx f_typ 0))
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types_match (lambda (t1 t2) (= t1 t2))
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contains (let (contains-helper (rec-lambda recurse (s x i) (cond (= i (len s)) false
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(= x (idx s i)) true
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true (recurse s x (+ i 1)))))
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(lambda (s x) (contains-helper s x 0)))
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execute_type_com (lambda (tc e) (tc e))
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applyST (rec-lambda recurse (S t)
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(cond
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(int? t) (or (lookup S t) t)
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(array? t) (map (lambda (x) (recurse S x)) t)
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true t
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))
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applySE (lambda (S env) (map (lambda (x) [(idx x 0) (applyST S (idx x 1))]) env))
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applySS (lambda (S_0 S_1) (let (r (concat S_0 (applySE S_0 S_1)) _ (println "applySS of " S_0 " and " S_1 " is " r)) r))
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fvT (rec-lambda recurse (t) (cond (symbol? t) [t]
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(array? t) (flat_map recurse t)
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true []
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))
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fvE (lambda (env) (flat_map (lambda (x) (fvT (idx x 1))) env))
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varBind (lambda (a b) (cond
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(= a b) []
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(contains (fvT b) a) (error "Contains check failed for " a " and " b)
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true [ [a b] ]))
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mgu (rec-lambda mgu (a b) (let (r (cond
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(and (array? a) (array? b) (= (len a) (len b))) ((rec-lambda recurse (S i) (if (= i (len a)) S
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(recurse (applySS (mgu (idx a i) (idx b i)) S) (+ 1 i)))) [] 0)
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(int? a) (varBind a b)
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(int? b) (varBind b a)
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(= a b) []
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true (error (str "Cannot unify " a " " b))
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) _ (println "mgu of " a " and " b " is " r)) r))
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simple_type_com (lambda (exp typ) (lambda (env) (with_type exp typ)))
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symbol_type_com (lambda (sym) (lambda (env) (with_type sym (lookup env sym))))
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execute_type_com (lambda (tc e idn) (tc e idn))
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simple_type_com (lambda (exp typ) (lambda (env idn) [exp typ [] idn]))
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symbol_type_com (lambda (sym) (lambda (env idn) [sym (lookup env sym) [] idn]))
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parameter_types_match (let (pmth (rec-lambda recurse (l1 l2 i) (cond (= i (len l1)) true
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(types_match (idx l1 i) (idx l2 i)) (recurse l1 l2 (+ i 1))
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true false)))
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(lambda (f_t pt) (let (fp_t (get_params_typs f_t))
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(if (= (len fp_t) (len pt))
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(pmth fp_t pt 0)
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false))))
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call_type_com (lambda (innards)
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(lambda (env)
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(lambda (env idn)
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(if (= 0 (len innards)) (error "stlc_error: Can't have a 0-length call")
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(let (
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f_et (execute_type_com (idx innards 0) env)
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f_e (get_exp f_et)
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f_t (get_typ f_et)
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p_et (map (lambda (x) (execute_type_com x env)) (slice innards 1 -1))
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p_e (map get_exp p_et)
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p_t (map get_typ p_et)
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) (if (parameter_types_match f_t p_t)
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(with_type (cons f_e p_e) (get_ret_typ f_t))
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(error (str "Function type (" f_t ") does not match parameter types (" p_t ")"))
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)
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)
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(f_e f_t S_0 idn) (execute_type_com (idx innards 0) env idn)
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across_params (rec-lambda recurse (env S idn params i out_e out_t)
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(if (= i (len params)) [out_e out_t S idn]
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(let (
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(p_e p_t S_i idn) (execute_type_com (idx params i) env idn)
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) (recurse (applySE S_i env) (applySS S_i S) idn params (+ 1 i) (concat out_e [p_e]) (concat out_t [p_t])))))
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(p_es p_ts S_ps idn) (across_params (applySE S_0 env) [] idn (slice innards 1 -1) 0 [] [])
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(r_t idn) [idn (+ 1 idn)]
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S_f (mgu (applyST S_ps f_t) [p_ts r_t])
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_ (println "mgu of " (applyST S_ps f_t) " and " [p_ts r_t] " produces substitution " S_f)
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_ (println "For this call: " (cons f_e p_es) " the return type " r_t " transformed by " S_f " is " (applyST S_f r_t))
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) [(cons f_e p_es) (applyST S_f r_t) (applySS S_f (applySS S_ps S_0)) idn])
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)
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)
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)
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lambda_type_com (lambda (p t b)
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(lambda (env)
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(lambda (env idn)
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(let (
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extended_env (cons [p t] env)
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b_et (execute_type_com b extended_env)
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b_t (get_typ b_et)
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b_e (get_exp b_et)
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(p_t idn) (if (= nil t) [idn (+ 1 idn)]
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[t idn])
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extended_env (cons [p p_t] env)
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(b_e b_t S idn) (execute_type_com b extended_env idn)
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f_e [lambda [p] b_e]
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f_t [[t] b_t]
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) (with_type f_e f_t))
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f_t [[ (applyST S p_t) ] b_t]
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) [f_e f_t S idn])
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)
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)
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@@ -68,6 +86,10 @@
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current_env (vau de () de)
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syms (map (lambda (x) (idx x 0)) base_env)
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builtin_real_env (eval (concat (vapply provide syms root_env) [[current_env]]) empty_env)
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top-level-erase-and-check (lambda (e) (let (
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(e t S idn) (execute_type_com e base_env 0)
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_ (println "Type of program is " t " with sub " S)
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) e))
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stlc (concat basic_rules [
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@@ -80,12 +102,13 @@
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)
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) ]
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[ 'expr [ "\\\\" 'WS * 'bool_nil_symbol 'WS * ":" 'WS * 'bool_nil_symbol 'WS * "." 'WS * 'expr ] (lambda (_ _ p _ _ _ t _ _ _ b) (lambda_type_com p t b)) ]
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[ 'expr [ "\\\\" 'WS * 'bool_nil_symbol 'WS * "." 'WS * 'expr ] (lambda (_ _ p _ _ _ b) (lambda_type_com p nil b)) ]
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[ 'call_innards [ 'WS * ] (lambda (_) []) ]
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[ 'call_innards [ 'expr [ 'WS 'expr ] * ] (lambda (f r) (cons f (map (lambda (x) (idx x 1)) r))) ]
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[ 'expr [ "\\(" 'call_innards "\\)" ] (lambda (_ innards _) (call_type_com innards)) ]
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[ 'stlc_start_symbol [ 'WS * 'expr 'WS * ] (lambda (_ e _) [eval (get_exp (execute_type_com e base_env)) builtin_real_env]) ]
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[ 'stlc_start_symbol [ 'WS * 'expr 'WS * ] (lambda (_ e _) [eval (top-level-erase-and-check e) builtin_real_env]) ]
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]))
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(provide stlc)
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