syntax: implement support for ES6 template literals

Implement support for ECMAScript 6 template literals which allow simple
interpolation of variable values into strings without resorting to
`sprintf()` or manual string concatenation.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 23 insertions, 0 deletions

diff --git a/compiler.c b/compiler.c
index 80b873d..d4725b1 100644
--- a/compiler.c
+++ b/compiler.c
@@ -33,6 +33,7 @@ static void uc_compiler_compile_paren(uc_compiler_t *compiler);
 static void uc_compiler_compile_call(uc_compiler_t *compiler);
 static void uc_compiler_compile_post_inc(uc_compiler_t *compiler);
 static void uc_compiler_compile_constant(uc_compiler_t *compiler);
+static void uc_compiler_compile_template(uc_compiler_t *compiler);
 static void uc_compiler_compile_comma(uc_compiler_t *compiler);
 static void uc_compiler_compile_labelexpr(uc_compiler_t *compiler);
 static void uc_compiler_compile_function(uc_compiler_t *compiler);
@@ -72,6 +73,7 @@ uc_compiler_parse_rules[TK_ERROR + 1] = {
 	[TK_NULL]		= { uc_compiler_compile_constant, NULL, P_NONE },
 	[TK_THIS]		= { uc_compiler_compile_constant, NULL, P_NONE },
 	[TK_REGEXP]		= { uc_compiler_compile_constant, NULL, P_NONE },
+	[TK_TEMPLATE]	= { uc_compiler_compile_template, NULL, P_NONE },
 	[TK_COMMA]		= { NULL, uc_compiler_compile_comma, P_COMMA },
 	[TK_LABEL]		= { uc_compiler_compile_labelexpr, NULL, P_NONE },
 	[TK_FUNC]		= { uc_compiler_compile_function, NULL, P_NONE },
@@ -1484,6 +1486,27 @@ uc_compiler_compile_constant(uc_compiler_t *compiler)
 }
 
 static void
+uc_compiler_compile_template(uc_compiler_t *compiler)
+{
+	uc_compiler_emit_constant(compiler, compiler->parser->prev.pos, compiler->parser->prev.uv);
+
+	while (true) {
+		if (uc_compiler_parse_match(compiler, TK_TEMPLATE)) {
+			uc_compiler_emit_constant(compiler, compiler->parser->prev.pos, compiler->parser->prev.uv);
+			uc_compiler_emit_insn(compiler, 0, I_ADD);
+		}
+		else if (uc_compiler_parse_match(compiler, TK_PLACEH)) {
+			uc_compiler_compile_expression(compiler);
+			uc_compiler_emit_insn(compiler, 0, I_ADD);
+			uc_compiler_parse_consume(compiler, TK_RBRACE);
+		}
+		else {
+			break;
+		}
+	}
+}
+
+static void
 uc_compiler_compile_comma(uc_compiler_t *compiler)
 {
 	uc_compiler_emit_insn(compiler, 0, I_POP);