From 0283ab8a1a27c9d3a7a6d88960418485a7125d1d Mon Sep 17 00:00:00 2001
From: Vexu <git@vexu.eu>
Date: Tue, 17 Dec 2019 12:06:28 +0200
Subject: [PATCH] translate-c-2 conditional operator

---
 src-self-hosted/clang.zig       |  4 ++++
 src-self-hosted/translate_c.zig | 42 +++++++++++++++++++++++++++++++--
 test/translate_c.zig            | 12 ++++++++++
 3 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/src-self-hosted/clang.zig b/src-self-hosted/clang.zig
index 559a4ad0e5..dcb830df69 100644
--- a/src-self-hosted/clang.zig
+++ b/src-self-hosted/clang.zig
@@ -1055,3 +1055,7 @@ pub extern fn ZigClangForStmt_getBody(*const ZigClangForStmt) *const ZigClangStm
 
 pub extern fn ZigClangAPFloat_toString(self: *const ZigClangAPFloat, precision: c_uint, maxPadding: c_uint, truncateZero: bool) [*:0]const u8;
 pub extern fn ZigClangAPFloat_getValueAsApproximateDouble(*const ZigClangFloatingLiteral) f64;
+
+pub extern fn ZigClangConditionalOperator_getCond(*const ZigClangConditionalOperator) *const ZigClangExpr;
+pub extern fn ZigClangConditionalOperator_getTrueExpr(*const ZigClangConditionalOperator) *const ZigClangExpr;
+pub extern fn ZigClangConditionalOperator_getFalseExpr(*const ZigClangConditionalOperator) *const ZigClangExpr;
diff --git a/src-self-hosted/translate_c.zig b/src-self-hosted/translate_c.zig
index 4cdef9f805..79b32c2fa2 100644
--- a/src-self-hosted/translate_c.zig
+++ b/src-self-hosted/translate_c.zig
@@ -633,6 +633,7 @@ fn transStmt(
         .BreakStmtClass => return transBreak(rp, scope),
         .ForStmtClass => return transForLoop(rp, scope, @ptrCast(*const ZigClangForStmt, stmt)),
         .FloatingLiteralClass => return transFloatingLiteral(rp, scope, @ptrCast(*const ZigClangFloatingLiteral, stmt), result_used),
+        .ConditionalOperatorClass => return transConditionalOperator(rp, scope, @ptrCast(*const ZigClangConditionalOperator, stmt), result_used),
         else => {
             return revertAndWarn(
                 rp,
@@ -1239,11 +1240,11 @@ fn transIfStmt(
     if_node.condition = try transBoolExpr(rp, &cond_scope.base, @ptrCast(*const ZigClangExpr, ZigClangIfStmt_getCond(stmt)), .used, .r_value, false);
     _ = try appendToken(rp.c, .RParen, ")");
 
-    if_node.body = try transStmt(rp, scope, ZigClangIfStmt_getThen(stmt), .used, .r_value);
+    if_node.body = try transStmt(rp, scope, ZigClangIfStmt_getThen(stmt), .unused, .r_value);
 
     if (ZigClangIfStmt_getElse(stmt)) |expr| {
         if_node.@"else" = try transCreateNodeElse(rp.c);
-        if_node.@"else".?.body = try transStmt(rp, scope, expr, .used, .r_value);
+        if_node.@"else".?.body = try transStmt(rp, scope, expr, .unused, .r_value);
     }
     _ = try appendToken(rp.c, .Semicolon, ";");
     return &if_node.base;
@@ -1429,6 +1430,43 @@ fn transFloatingLiteral(rp: RestorePoint, scope: *Scope, stmt: *const ZigClangFl
     return maybeSuppressResult(rp, scope, used, &node.base);
 }
 
+fn transConditionalOperator(rp: RestorePoint, scope: *Scope, stmt: *const ZigClangConditionalOperator, used: ResultUsed) TransError!*ast.Node {
+    const gropued = scope.id == .Condition;
+    const lparen = if (gropued) try appendToken(rp.c, .LParen, "(") else undefined;
+    const if_node = try transCreateNodeIf(rp.c);
+    var cond_scope = Scope.Condition{
+        .base = .{
+            .parent = scope,
+            .id = .Condition,
+        },
+    };
+
+    const cond_expr = ZigClangConditionalOperator_getCond(stmt);
+    const true_expr = ZigClangConditionalOperator_getTrueExpr(stmt);
+    const false_expr = ZigClangConditionalOperator_getFalseExpr(stmt);
+
+    if_node.condition = try transBoolExpr(rp, &cond_scope.base, cond_expr, .used, .r_value, false);
+    _ = try appendToken(rp.c, .RParen, ")");
+
+    if_node.body = try transExpr(rp, scope, true_expr, .used, .r_value);
+
+    if_node.@"else" = try transCreateNodeElse(rp.c);
+    if_node.@"else".?.body = try transExpr(rp, scope, false_expr, .used, .r_value);
+
+    if (gropued) {
+        const rparen = try appendToken(rp.c, .RParen, ")");
+        const grouped_expr = try rp.c.a().create(ast.Node.GroupedExpression);
+        grouped_expr.* = .{
+            .lparen = lparen,
+            .expr =  &if_node.base,
+            .rparen = rparen,
+        };
+        return maybeSuppressResult(rp, scope, used, &grouped_expr.base);
+    } else {
+        return maybeSuppressResult(rp, scope, used, &if_node.base);
+    }
+}
+
 fn maybeSuppressResult(
     rp: RestorePoint,
     scope: *Scope,
diff --git a/test/translate_c.zig b/test/translate_c.zig
index 02ba62a471..c4fb63799c 100644
--- a/test/translate_c.zig
+++ b/test/translate_c.zig
@@ -837,6 +837,18 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
         \\pub export var d: f64 = @intToFloat(f64, 3);
     });
 
+    cases.add_2("conditional operator",
+        \\int bar(void) {
+        \\    if (2 ? 5 : 5 ? 4 : 6) 2;
+        \\    return  2 ? 5 : 5 ? 4 : 6;
+        \\}
+    , &[_][]const u8{
+        \\pub export fn bar() c_int {
+        \\    if ((if (2 != 0) 5 else (if (5 != 0) 4 else 6)) != 0) _ = 2;
+        \\    return if (2 != 0) 5 else if (5 != 0) 4 else 6;
+        \\}
+    });
+
     /////////////// Cases for only stage1 which are TODO items for stage2 ////////////////
 
     if (builtin.os != builtin.Os.windows) {