From 322a9992e55e566ebf33cdcd3107d59d7eadeb19 Mon Sep 17 00:00:00 2001 From: Nicolas Dandrimont Date: Fri, 10 May 2013 23:11:31 +0200 Subject: [PATCH] Implement unquote and unquote-splicing --- hy/compiler.py | 64 +++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 53 insertions(+), 11 deletions(-) diff --git a/hy/compiler.py b/hy/compiler.py index 88b1dff..d008a2b 100644 --- a/hy/compiler.py +++ b/hy/compiler.py @@ -494,33 +494,75 @@ class HyASTCompiler(object): ret += ret.expr_as_stmt() return ret - def _render_quoted_form(self, form): + def _render_quoted_form(self, form, level=0): + """ + Render a quoted form as a new HyExpression. + + `level` is the level of quasiquoting of the current form. We can + unquote if level is 0. + + Returns a three-tuple (`imports`, `expression`, `splice`). + + The `splice` return value is used to mark `unquote-splice`d forms. + We need to distinguish them as want to concatenate them instead of + just nesting them. + """ + if level == 0: + if isinstance(form, HyExpression): + if form and form[0] in ("unquote", "unquote_splice"): + if len(form) != 2: + raise HyTypeError(form, + ("`%s' needs 1 argument, got %s" % + form[0], len(form) - 1)) + return set(), form[1], (form[0] == "unquote_splice") + + if isinstance(form, HyExpression): + if form and form[0] == "quote": + level += 1 + if form and form[0] in ("unquote", "unquote_splice"): + level -= 1 + name = form.__class__.__name__ - imports = [name] + imports = set([name]) if isinstance(form, HyList): - contents = [] + contents = HyList() for x in form: - form_imports, form_contents = self._render_quoted_form(x) - imports += form_imports - contents.append(form_contents) + f_imports, f_contents, splice = self._render_quoted_form(x, + level) + imports.update(f_imports) + if splice: + contents = HyExpression([HySymbol('+'), + contents, + f_contents]) + else: + contents.append(f_contents) return imports, HyExpression( [HySymbol(name), - HyList(contents)] - ).replace(form) + contents] + ).replace(form), False + elif isinstance(form, HySymbol): return imports, HyExpression([HySymbol(name), - HyString(form)]).replace(form) - return imports, HyExpression([HySymbol(name), form]).replace(form) + HyString(form)]).replace(form), False + + return imports, HyExpression([HySymbol(name), + form]).replace(form), False @builds("quote") @checkargs(exact=1) def compile_quote(self, entries): - imports, stmts = self._render_quoted_form(entries[1]) + imports, stmts, splice = self._render_quoted_form(entries[1]) ret = self.compile(stmts) ret.add_imports("hy", imports) return ret + @builds("unquote") + @builds("unquote-splicing") + def compile_unquote(self, expr): + raise HyTypeError(expr, + "`%s' can't be used at the top-level" % expr[0]) + @builds("eval") @checkargs(exact=1) def compile_eval(self, expr):