shell/math: fix ?: to not evaluate not-taken branches

This fixes ash-arith-arith-ternary1/2.tests

function                                             old     new   delta
evaluate_string                                     1271    1432    +161
arith_apply                                          968    1000     +32
arith                                                 22      36     +14
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 207/0)             Total: 207 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

10 files changed, 25 insertions, 0 deletions

diff --git a/shell/ash_test/ash-arith/arith-ternary-assign.right b/shell/ash_test/ash-arith/arith-ternary-assign.right
new file mode 100644
index 000000000..6644d86bf
--- /dev/null
+++ b/shell/ash_test/ash-arith/arith-ternary-assign.right
@@ -0,0 +1 @@
+42:42
diff --git a/shell/ash_test/ash-arith/arith-ternary-assign.tests b/shell/ash_test/ash-arith/arith-ternary-assign.tests
new file mode 100755
index 000000000..fa18fe7b9
--- /dev/null
+++ b/shell/ash_test/ash-arith/arith-ternary-assign.tests
@@ -0,0 +1,3 @@
+exec 2>&1
+a='@'
+echo 42:$((a=1?42:3,a))
diff --git a/shell/ash_test/ash-arith/arith-ternary-comma.right b/shell/ash_test/ash-arith/arith-ternary-comma.right
new file mode 100644
index 000000000..6644d86bf
--- /dev/null
+++ b/shell/ash_test/ash-arith/arith-ternary-comma.right
@@ -0,0 +1 @@
+42:42
diff --git a/shell/ash_test/ash-arith/arith-ternary-comma.tests b/shell/ash_test/ash-arith/arith-ternary-comma.tests
new file mode 100755
index 000000000..5e05b58c4
--- /dev/null
+++ b/shell/ash_test/ash-arith/arith-ternary-comma.tests
@@ -0,0 +1,3 @@
+exec 2>&1
+x='@'
+echo 42:$((1?4:x,20*2+2))
diff --git a/shell/ash_test/ash-arith/arith-ternary-preincr.right b/shell/ash_test/ash-arith/arith-ternary-preincr.right
new file mode 100644
index 000000000..6644d86bf
--- /dev/null
+++ b/shell/ash_test/ash-arith/arith-ternary-preincr.right
@@ -0,0 +1 @@
+42:42
diff --git a/shell/ash_test/ash-arith/arith-ternary-preincr.tests b/shell/ash_test/ash-arith/arith-ternary-preincr.tests
new file mode 100755
index 000000000..3985c7079
--- /dev/null
+++ b/shell/ash_test/ash-arith/arith-ternary-preincr.tests
@@ -0,0 +1,3 @@
+exec 2>&1
+x='@'
+echo 42:$((1?42:++x))
diff --git a/shell/ash_test/ash-arith/arith-ternary3.right b/shell/ash_test/ash-arith/arith-ternary3.right
new file mode 100644
index 000000000..6644d86bf
--- /dev/null
+++ b/shell/ash_test/ash-arith/arith-ternary3.right
@@ -0,0 +1 @@
+42:42
diff --git a/shell/ash_test/ash-arith/arith-ternary3.tests b/shell/ash_test/ash-arith/arith-ternary3.tests
new file mode 100755
index 000000000..0bf9f3002
--- /dev/null
+++ b/shell/ash_test/ash-arith/arith-ternary3.tests
@@ -0,0 +1,4 @@
+exec 2>&1
+# "EXPR ?..." should check _evaluated_ EXPR,
+# not its last value
+echo 42:$((1 < 1 ? -1 : 1 > 1 ? 1 : 42))
diff --git a/shell/ash_test/ash-arith/arith-ternary_nested3.right b/shell/ash_test/ash-arith/arith-ternary_nested3.right
new file mode 100644
index 000000000..1a34fde65
--- /dev/null
+++ b/shell/ash_test/ash-arith/arith-ternary_nested3.right
@@ -0,0 +1,2 @@
+42:42
+a=2:2
diff --git a/shell/ash_test/ash-arith/arith-ternary_nested3.tests b/shell/ash_test/ash-arith/arith-ternary_nested3.tests
new file mode 100755
index 000000000..b69dcc6e9
--- /dev/null
+++ b/shell/ash_test/ash-arith/arith-ternary_nested3.tests
@@ -0,0 +1,6 @@
+exec 2>&1
+x='@'
+a=2
+# After processing nested ?:, outermost ?: should still rememeber to NOT evaluate a*=2
+echo 42:$((1?0?41:42:(a*=2)))
+echo "a=2:$a"