## lustrec / src / init_calculus.ml @ d4c98bae

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1 | a2d97a3e | ploc | (********************************************************************) |
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2 | (* *) |
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3 | (* The LustreC compiler toolset / The LustreC Development Team *) |
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4 | (* Copyright 2012 - -- ONERA - CNRS - INPT *) |
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5 | (* *) |
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6 | (* LustreC is free software, distributed WITHOUT ANY WARRANTY *) |
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7 | (* under the terms of the GNU Lesser General Public License *) |
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8 | (* version 2.1. *) |
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9 | (* *) |
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10 | (********************************************************************) |
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11 | 22fe1c93 | ploc | |

12 | (** Main typing module. Classic inference algorithm with destructive |
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13 | unification. *) |
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14 | |||

15 | (* Though it shares similarities with the clock calculus module, no code |
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16 | is shared. Simple environments, very limited identifier scoping, no |
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17 | identifier redefinition allowed. *) |
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18 | |||

19 | open Utils |
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20 | (* Yes, opening both modules is dirty as some type names will be |
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21 | overwritten, yet this makes notations far lighter.*) |
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22 | open Corelang |
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23 | open Init |
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24 | open Format |
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25 | |||

26 | (** [occurs tvar ty] returns true if the type variable [tvar] occurs in |
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27 | type [ty]. False otherwise. *) |
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28 | let rec occurs tvar ty = |
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29 | let ty = repr ty in |
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30 | match ty.tdesc with |
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31 | | Ivar -> ty=tvar |
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32 | | Iarrow (t1, t2) -> |
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33 | (occurs tvar t1) || (occurs tvar t2) |
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34 | | Ituple tl -> |
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35 | List.exists (occurs tvar) tl |
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36 | | Ilink t -> occurs tvar t |
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37 | | Isucc t -> occurs tvar t |
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38 | | Iunivar -> false |
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39 | |||

40 | (** Promote monomorphic type variables to polymorphic type variables. *) |
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41 | (* Generalize by side-effects *) |
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42 | let rec generalize ty = |
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43 | match ty.tdesc with |
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44 | | Ivar -> |
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45 | (* No scopes, always generalize *) |
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46 | ty.idesc <- Iunivar |
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47 | | Iarrow (t1,t2) -> |
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48 | generalize t1; generalize t2 |
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49 | | Ituple tlist -> |
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50 | List.iter generalize tlist |
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51 | | Ilink t -> |
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52 | generalize t |
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53 | | Isucc t -> |
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54 | generalize t |
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55 | | Tunivar -> () |
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56 | |||

57 | (** Downgrade polymorphic type variables to monomorphic type variables *) |
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58 | let rec instanciate inst_vars ty = |
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59 | let ty = repr ty in |
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60 | match ty.idesc with |
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61 | | Ivar -> ty |
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62 | | Iarrow (t1,t2) -> |
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63 | {ty with idesc = |
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64 | Iarrow ((instanciate inst_vars t1), (instanciate inst_vars t2))} |
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65 | | Ituple tlist -> |
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66 | {ty with idesc = Ituple (List.map (instanciate inst_vars) tlist)} |
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67 | | Isucc t -> |
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68 | (* should not happen *) |
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69 | {ty with idesc = Isucc (instanciate inst_vars t)} |
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70 | | Ilink t -> |
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71 | (* should not happen *) |
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72 | {ty with idesc = Ilink (instanciate inst_vars t)} |
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73 | | Iunivar -> |
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74 | try |
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75 | List.assoc ty.iid !inst_vars |
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76 | with Not_found -> |
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77 | let var = new_var () in |
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78 | inst_vars := (ty.iid, var)::!inst_vars; |
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79 | var |
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80 | |||

81 | (** [unify env t1 t2] unifies types [t1] and [t2]. Raises [Unify |
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82 | (t1,t2)] if the types are not unifiable.*) |
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83 | |||

84 | (* Standard destructive unification *) |
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85 | (* may loop for omega types *) |
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86 | let rec unify t1 t2 = |
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87 | let t1 = repr t1 in |
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88 | let t2 = repr t2 in |
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89 | if t1=t2 then |
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90 | () |
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91 | else |
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92 | (* No type abbreviations resolution for now *) |
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93 | match t1.idesc,t2.idesc with |
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94 | (* This case is not mandory but will keep "older" types *) |
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95 | | Ivar, Ivar -> |
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96 | if t1.iid < t2.iid then |
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97 | t2.idesc <- Ilink t1 |
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98 | else |
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99 | t1.idesc <- Ilink t2 |
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100 | | (Ivar, _) when (not (occurs t1 t2)) -> |
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101 | t1.idesc <- Ilink t2 |
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102 | | (_,Ivar) when (not (occurs t2 t1)) -> |
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103 | t2.idesc <- Ilink t1 |
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104 | | Isucc t1, Isucc t1' -> unify t1 t1' |
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105 | | Iarrow (t1,t2), Iarrow (t1',t2') -> |
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106 | unify t1 t1'; unify t2 t2' |
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107 | | Ituple tlist1, Ituple tlist2 -> |
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108 | if (List.length tlist1) <> (List.length tlist2) then |
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109 | raise (Unify (t1, t2)) |
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110 | else |
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111 | List.iter2 unify tlist1 tlist2 |
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112 | | Iunivar,_ | _, Iunivar -> |
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113 | () |
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114 | | _,_ -> raise (Unify (t1, t2)) |
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115 | |||

116 | let init_of_const c = |
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117 | Init_predef.init_zero |
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118 | |||

119 | let rec init_expect env in_main expr ty = |
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120 | let texpr = init_expr env in_main expr in |
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121 | try |
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122 | unify texpr ty |
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123 | with Unify (t1,t2) -> |
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124 | raise (Error (expr.expr_loc, Init_clash (t1,t2))) |
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125 | |||

126 | and init_ident env in_main id loc = |
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127 | init_expr env in_main (expr_of_ident id loc) |
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128 | |||

129 | (** [type_expr env in_main expr] types expression [expr] in environment |
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130 | [env]. *) |
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131 | and init_expr env in_main expr = |
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132 | match expr.expr_desc with |
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133 | | Expr_const c -> |
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134 | let ty = init_of_const c in |
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135 | expr.expr_init <- ty; |
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136 | ty |
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137 | | Expr_ident v -> |
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138 | let tyv = |
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139 | try |
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140 | Env.lookup_value env v |
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141 | with Not_found -> |
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142 | raise (Error (expr.expr_loc, Unbound_value v)) |
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143 | in |
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144 | let ty = instanciate (ref []) tyv in |
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145 | expr.expr_init <- ty; |
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146 | ty |
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147 | | Expr_tuple elist -> |
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148 | let ty = new_ty (Ttuple (List.map (type_expr env in_main) elist)) in |
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149 | expr.expr_init <- ty; |
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150 | ty |
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151 | | Expr_appl (id, args, r) -> |
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152 | (match r with |
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153 | | None -> () |
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154 | | Some x -> let expr_x = expr_of_ident x expr.expr_loc in |
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155 | init_expect env in_main expr_x Init_predef.init_zero); |
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156 | let tfun = type_ident env in_main id expr.expr_loc in |
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157 | let tins,touts= split_arrow tfun in |
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158 | type_expect env in_main args tins; |
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159 | expr.expr_type <- touts; |
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160 | touts |
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161 | | Expr_arrow (e1,e2) -> |
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162 | let ty = type_expr env in_main e1 in |
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163 | type_expect env in_main e2 ty; |
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164 | expr.expr_type <- ty; |
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165 | ty |
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166 | | Expr_fby (init,e) -> |
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167 | let ty = type_of_const init in |
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168 | type_expect env in_main e ty; |
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169 | expr.expr_type <- ty; |
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170 | ty |
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171 | | Expr_concat (hd,e) -> |
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172 | let ty = type_of_const hd in |
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173 | type_expect env in_main e ty; |
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174 | expr.expr_type <- ty; |
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175 | ty |
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176 | | Expr_tail e -> |
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177 | let ty = type_expr env in_main e in |
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178 | expr.expr_type <- ty; |
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179 | ty |
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180 | | Expr_pre e -> |
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181 | let ty = type_expr env in_main e in |
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182 | expr.expr_type <- ty; |
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183 | ty |
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184 | | Expr_when (e1,c) | Expr_whennot (e1,c) -> |
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185 | let expr_c = expr_of_ident c expr.expr_loc in |
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186 | type_expect env in_main expr_c Type_predef.type_bool; |
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187 | let tlarg = type_expr env in_main e1 in |
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188 | expr.expr_type <- tlarg; |
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189 | tlarg |
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190 | | Expr_merge (c,e2,e3) -> |
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191 | let expr_c = expr_of_ident c expr.expr_loc in |
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192 | type_expect env in_main expr_c Type_predef.type_bool; |
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193 | let te2 = type_expr env in_main e2 in |
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194 | type_expect env in_main e3 te2; |
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195 | expr.expr_type <- te2; |
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196 | te2 |
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197 | | Expr_uclock (e,k) | Expr_dclock (e,k) -> |
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198 | let ty = type_expr env in_main e in |
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199 | expr.expr_type <- ty; |
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200 | ty |
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201 | | Expr_phclock (e,q) -> |
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202 | let ty = type_expr env in_main e in |
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203 | expr.expr_type <- ty; |
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204 | ty |
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205 | |||

206 | (** [type_eq env eq] types equation [eq] in environment [env] *) |
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207 | let type_eq env in_main undefined_vars eq = |
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208 | (* Check multiple variable definitions *) |
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209 | let define_var id uvars = |
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210 | try |
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211 | ignore(IMap.find id uvars); |
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212 | IMap.remove id uvars |
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213 | with Not_found -> |
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214 | raise (Error (eq.eq_loc, Already_defined id)) |
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215 | in |
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216 | let undefined_vars = |
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217 | List.fold_left (fun uvars v -> define_var v uvars) undefined_vars eq.eq_lhs in |
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218 | (* Type lhs *) |
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219 | let get_value_type id = |
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220 | try |
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221 | Env.lookup_value env id |
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222 | with Not_found -> |
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223 | raise (Error (eq.eq_loc, Unbound_value id)) |
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224 | in |
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225 | let tyl_lhs = List.map get_value_type eq.eq_lhs in |
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226 | let ty_lhs = type_of_type_list tyl_lhs in |
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227 | (* Type rhs *) |
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228 | type_expect env in_main eq.eq_rhs ty_lhs; |
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229 | undefined_vars |
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230 | |||

231 | (* [type_coretype cty] types the type declaration [cty] *) |
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232 | let type_coretype cty = |
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233 | match cty with |
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234 | | Tydec_any -> new_var () |
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235 | | Tydec_int -> Type_predef.type_int |
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236 | | Tydec_real -> Type_predef.type_real |
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237 | | Tydec_float -> Type_predef.type_real |
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238 | | Tydec_bool -> Type_predef.type_bool |
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239 | | Tydec_clock -> Type_predef.type_clock |
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240 | |||

241 | (* [type_coreclock env ck id loc] types the type clock declaration [ck] |
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242 | in environment [env] *) |
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243 | let type_coreclock env ck id loc = |
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244 | match ck.ck_dec_desc with |
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245 | | Ckdec_any | Ckdec_pclock (_,_) -> () |
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246 | | Ckdec_bool cl -> |
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247 | let dummy_id_expr = expr_of_ident id loc in |
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248 | let when_expr = |
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249 | List.fold_left |
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250 | (fun expr c -> |
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251 | match c with |
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252 | | Wtrue id -> |
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253 | {expr_tag = new_tag (); |
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254 | expr_desc=Expr_when (expr,id); |
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255 | expr_type = new_var (); |
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256 | expr_clock = Clocks.new_var true; |
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257 | expr_loc=loc} |
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258 | | Wfalse id -> |
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259 | {expr_tag = new_tag (); |
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260 | expr_desc=Expr_whennot (expr,id); |
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261 | expr_type = new_var (); |
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262 | expr_clock = Clocks.new_var true; |
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263 | expr_loc=loc}) |
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264 | dummy_id_expr cl |
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265 | in |
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266 | ignore (type_expr env false when_expr) |
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267 | |||

268 | let type_var_decl env vdecl = |
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269 | if (Env.exists_value env vdecl.var_id) then |
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270 | raise (Error (vdecl.var_loc,Already_bound vdecl.var_id)) |
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271 | else |
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272 | let ty = type_coretype vdecl.var_dec_type.ty_dec_desc in |
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273 | let new_env = Env.add_value env vdecl.var_id ty in |
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274 | type_coreclock new_env vdecl.var_dec_clock vdecl.var_id vdecl.var_loc; |
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275 | vdecl.var_type <- ty; |
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276 | new_env |
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277 | |||

278 | let type_var_decl_list env l = |
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279 | List.fold_left type_var_decl env l |
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280 | |||

281 | let type_of_vlist vars = |
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282 | let tyl = List.map (fun v -> v.var_type) vars in |
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283 | type_of_type_list tyl |
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284 | |||

285 | (** [type_node env nd loc] types node [nd] in environment env. The |
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286 | location is used for error reports. *) |
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287 | let type_node env nd loc = |
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288 | let is_main = nd.node_id = !Options.main_node in |
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289 | let delta_env = type_var_decl_list IMap.empty nd.node_inputs in |
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290 | let delta_env = type_var_decl_list delta_env nd.node_outputs in |
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291 | let delta_env = type_var_decl_list delta_env nd.node_locals in |
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292 | let new_env = Env.overwrite env delta_env in |
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293 | let undefined_vars_init = |
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294 | List.fold_left |
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295 | (fun uvs v -> IMap.add v.var_id () uvs) |
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296 | IMap.empty (nd.node_outputs@nd.node_locals) in |
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297 | let undefined_vars = |
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298 | List.fold_left (type_eq new_env is_main) undefined_vars_init nd.node_eqs |
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299 | in |
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300 | (* check that table is empty *) |
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301 | if (not (IMap.is_empty undefined_vars)) then |
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302 | raise (Error (loc,Undefined_var undefined_vars)); |
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303 | let ty_ins = type_of_vlist nd.node_inputs in |
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304 | let ty_outs = type_of_vlist nd.node_outputs in |
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305 | let ty_node = new_ty (Tarrow (ty_ins,ty_outs)) in |
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306 | generalize ty_node; |
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307 | (* TODO ? Check that no node in the hierarchy remains polymorphic ? *) |
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308 | nd.node_type <- ty_node; |
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309 | Env.add_value env nd.node_id ty_node |
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310 | |||

311 | let type_imported_node env nd loc = |
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312 | let new_env = type_var_decl_list env nd.nodei_inputs in |
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313 | ignore(type_var_decl_list new_env nd.nodei_outputs); |
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314 | let ty_ins = type_of_vlist nd.nodei_inputs in |
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315 | let ty_outs = type_of_vlist nd.nodei_outputs in |
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316 | let ty_node = new_ty (Tarrow (ty_ins,ty_outs)) in |
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317 | generalize ty_node; |
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318 | if (is_polymorphic ty_node) then |
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319 | raise (Error (loc, Poly_imported_node nd.nodei_id)); |
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320 | let new_env = Env.add_value env nd.nodei_id ty_node in |
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321 | nd.nodei_type <- ty_node; |
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322 | new_env |
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323 | |||

324 | let type_top_decl env decl = |
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325 | match decl.top_decl_desc with |
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326 | | Node nd -> |
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327 | type_node env nd decl.top_decl_loc |
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328 | | ImportedNode nd -> |
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329 | type_imported_node env nd decl.top_decl_loc |
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330 | | SensorDecl _ | ActuatorDecl _ | Consts _ -> env |
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331 | |||

332 | let type_top_consts env decl = |
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333 | match decl.top_decl_desc with |
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334 | | Consts clist -> |
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335 | List.fold_left (fun env (id, c) -> |
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336 | let ty = type_of_const c in |
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337 | Env.add_value env id ty |
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338 | ) env clist |
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339 | | Node _ | ImportedNode _ | SensorDecl _ | ActuatorDecl _ -> env |
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340 | |||

341 | let type_prog env decls = |
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342 | let new_env = List.fold_left type_top_consts env decls in |
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343 | ignore(List.fold_left type_top_decl new_env decls) |
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344 | |||

345 | (* Local Variables: *) |
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346 | (* compile-command:"make -C .." *) |
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347 | (* End: *) |