fieldaccess.c

(80 lines)
   1 // This file defines how to compile field accessing like `foo.x`
   2 
   3 #include "../ast.h"
   4 #include "../config.h"
   5 #include "../environment.h"
   6 #include "../stdlib/tables.h"
   7 #include "../stdlib/text.h"
   8 #include "../stdlib/util.h"
   9 #include "../typecheck.h"
  10 #include "compilation.h"
  11 
  12 Text_t compile_field_access(env_t *env, ast_t *ast) {
  13     DeclareMatch(f, ast, FieldAccess);
  14     type_t *fielded_t = get_type(env, f->fielded);
  15     type_t *value_t = value_type(fielded_t);
  16     switch (value_t->tag) {
  17     case TypeInfoType: {
  18         DeclareMatch(info, value_t, TypeInfoType);
  19         if (f->field[0] == '_') {
  20             if (!type_eq(env->current_type, info->type))
  21                 code_err(ast, "Fields that start with underscores are not "
  22                               "accessible on outside of the type definition.");
  23         }
  24         binding_t *b = get_binding(info->env, f->field);
  25         if (!b) code_err(ast, "I couldn't find the field '", f->field, "' on this type");
  26         if (b->code.length == 0) code_err(ast, "I couldn't figure out how to compile this field");
  27         return b->code;
  28     }
  29     case TextType: {
  30         const char *lang = Match(value_t, TextType)->lang;
  31         if (lang && streq(f->field, "text")) {
  32             Text_t text = compile_to_pointer_depth(env, f->fielded, 0, false);
  33             return Texts("((Text_t)", text, ")");
  34         } else if (streq(f->field, "length")) {
  35             return Texts("Int$from_int64((", compile_to_pointer_depth(env, f->fielded, 0, false), ").length)");
  36         }
  37         code_err(ast, "There is no '", f->field, "' field on ", type_to_text(value_t), " values");
  38     }
  39     case StructType: {
  40         return compile_struct_field_access(env, ast);
  41     }
  42     case EnumType: {
  43         return compile_enum_field_access(env, ast);
  44     }
  45     case ListType: {
  46         if (streq(f->field, "length"))
  47             return Texts("Int$from_int64((", compile_to_pointer_depth(env, f->fielded, 0, false), ").length)");
  48         code_err(ast, "There is no ", f->field, " field on lists");
  49     }
  50     case TableType: {
  51         if (streq(f->field, "length")) {
  52             return Texts("Int$from_int64((", compile_to_pointer_depth(env, f->fielded, 0, false), ").entries.length)");
  53         } else if (streq(f->field, "keys")) {
  54             return Texts("LIST_COPY((", compile_to_pointer_depth(env, f->fielded, 0, false), ").entries)");
  55         } else if (streq(f->field, "values")) {
  56             DeclareMatch(table, value_t, TableType);
  57             Text_t offset = Texts("offsetof(struct { ", compile_declaration(table->key_type, Text("k")), "; ",
  58                                   compile_declaration(table->value_type, Text("v")), "; }, v)");
  59             return Texts("({ List_t *entries = &(", compile_to_pointer_depth(env, f->fielded, 0, false),
  60                          ").entries;\n"
  61                          "LIST_INCREF(*entries);\n"
  62                          "List_t values = *entries;\n"
  63                          "values.data += ",
  64                          offset,
  65                          ";\n"
  66                          "values; })");
  67         } else if (streq(f->field, "fallback")) {
  68             return Texts("({ Table_t *_fallback = (", compile_to_pointer_depth(env, f->fielded, 0, false),
  69                          ").fallback; _fallback ? *_fallback : NONE_TABLE; })");
  70         }
  71         code_err(ast, "There is no '", f->field, "' field on tables");
  72     }
  73     case ModuleType: {
  74         const char *name = Match(value_t, ModuleType)->name;
  75         env_t *module_env = Table$str_get(*env->imports, name);
  76         return compile(module_env, WrapAST(ast, Var, f->field));
  77     }
  78     default: code_err(ast, "Field accesses are not supported on ", type_to_text(fielded_t), " values");
  79     }
  80 }