diff options
Diffstat (limited to 'compile.c')
| -rw-r--r-- | compile.c | 37 |
1 files changed, 35 insertions, 2 deletions
@@ -2657,8 +2657,41 @@ CORD compile(env_t *env, ast_t *ast) code_err(call->fn, "This is not a function, it's a %T", fn_t); } } - case When: - code_err(ast, "'when' expressions are not yet implemented"); + case When: { + auto original = Match(ast, When); + ast_t *when_var = WrapAST(ast, Var, .name="when"); + when_clause_t *new_clauses = NULL; + type_t *subject_t = get_type(env, original->subject); + for (when_clause_t *clause = original->clauses; clause; clause = clause->next) { + type_t *clause_type = get_clause_type(env, subject_t, clause); + if (clause_type->tag == AbortType || clause_type->tag == ReturnType) { + new_clauses = new(when_clause_t, .tag_name=clause->tag_name, .args=clause->args, .body=clause->body, .next=new_clauses); + } else { + ast_t *assign = WrapAST(clause->body, Assign, + .targets=new(ast_list_t, .ast=when_var), + .values=new(ast_list_t, .ast=clause->body)); + new_clauses = new(when_clause_t, .tag_name=clause->tag_name, .args=clause->args, .body=assign, .next=new_clauses); + } + } + REVERSE_LIST(new_clauses); + ast_t *else_body = original->else_body; + if (else_body) { + type_t *clause_type = get_type(env, else_body); + if (clause_type->tag != AbortType && clause_type->tag != ReturnType) { + else_body = WrapAST(else_body, Assign, + .targets=new(ast_list_t, .ast=when_var), + .values=new(ast_list_t, .ast=else_body)); + } + } + + type_t *t = get_type(env, ast); + env_t *when_env = fresh_scope(env); + set_binding(when_env, "when", new(binding_t, .type=t, .code="when")); + return CORD_all( + "({ ", compile_declaration(t, "when"), ";\n", + compile_statement(when_env, WrapAST(ast, When, .subject=original->subject, .clauses=new_clauses, .else_body=else_body)), + "when; })"); + } case If: { auto if_ = Match(ast, If); if (!if_->else_body) |