From 8ef070bf94553a87c727fec8356eb26c82c982e8 Mon Sep 17 00:00:00 2001
From: "K. Lange" <klange@toaruos.org>
Date: Mon, 4 Jan 2021 07:47:05 +0900
Subject: [PATCH] Support 'from foo import bar, baz'

---
 compiler.c | 18 ++++++++++++++++++
 rline.c    |  2 +-
 scanner.c  |  5 ++++-
 scanner.h  |  1 +
 4 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/compiler.c b/compiler.c
index 288b9f0..da8ca9a 100644
--- a/compiler.c
+++ b/compiler.c
@@ -1263,6 +1263,22 @@ static void importStatement() {
 	defineVariable(ind);
 }
 
+static void fromImportStatement() {
+	consume(TOKEN_IDENTIFIER, "Expected module name after 'from'");
+	size_t ind = identifierConstant(&parser.previous);
+	EMIT_CONSTANT_OP(OP_IMPORT, ind);
+	consume(TOKEN_IMPORT, "Exported 'import' after module name");
+	do {
+		consume(TOKEN_IDENTIFIER, "Expected member name");
+		size_t member = identifierConstant(&parser.previous);
+		emitBytes(OP_DUP, 0); /* Duplicate the package object so we can GET_PROPERTY on it? */
+		EMIT_CONSTANT_OP(OP_GET_PROPERTY, member);
+		declareVariable();
+		defineVariable(member);
+	} while (match(TOKEN_COMMA));
+	emitByte(OP_POP); /* Pop the remaining copy of the module. */
+}
+
 static void exportStatement() {
 	do {
 		consume(TOKEN_IDENTIFIER, "only named variable may be exported to the global namespace");
@@ -1299,6 +1315,8 @@ static void statement() {
 			returnStatement();
 		} else if (match(TOKEN_IMPORT)) {
 			importStatement();
+		} else if (match(TOKEN_FROM)) {
+			fromImportStatement();
 		} else if (match(TOKEN_BREAK)) {
 			breakStatement();
 		} else if (match(TOKEN_CONTINUE)) {
diff --git a/rline.c b/rline.c
index 843c2bd..dbe7feb 100644
--- a/rline.c
+++ b/rline.c
@@ -521,7 +521,7 @@ void paint_krk_string(struct syntax_state * state, int type) {
 char * syn_krk_keywords[] = {
 	"and","class","def","else","export","for","if","in","import",
 	"let","not","or","print","return","while","try","except","raise",
-	"continue","break","as",
+	"continue","break","as","from",
 	NULL
 };
 
diff --git a/scanner.c b/scanner.c
index 461a74e..6334e27 100644
--- a/scanner.c
+++ b/scanner.c
@@ -208,7 +208,10 @@ static KrkTokenType identifierType() {
 				case 'c': return checkKeyword(3, "ept", TOKEN_EXCEPT);
 			} break;
 		} break;
-		case 'f': return checkKeyword(1, "or", TOKEN_FOR);
+		case 'f': if (MORE(1)) switch(scanner.start[1]) {
+			case 'o': return checkKeyword(2, "r", TOKEN_FOR);
+			case 'r': return checkKeyword(2, "om", TOKEN_FROM);
+		} break;
 		case 'F': return checkKeyword(1, "alse", TOKEN_FALSE);
 		case 'i': if (MORE(1)) switch (scanner.start[1]) {
 			case 'f': return checkKeyword(2, "", TOKEN_IF);
diff --git a/scanner.h b/scanner.h
index 5d8446d..c287dda 100644
--- a/scanner.h
+++ b/scanner.h
@@ -65,6 +65,7 @@ typedef enum {
 	TOKEN_MINUS_MINUS,/* -- */
 
 	TOKEN_AS,
+	TOKEN_FROM,
 
 	TOKEN_ERROR,
 	TOKEN_EOF,