gas: Generate code for if statement

If statements are now working, the only exception is for the comparators
|| and && that will be addressed in a further commit. Checks tested:

  fn main(): i32 {
    let n: i32 = 11;

    if (n == 11) {
      if n != 12 {
        if n < 12 {
          if n <= 11 {
            if n > 10 {
              if n >= 11 {
                return 42;
              }
            }
          }
        }
      }
    }

    return n;
  }

To compile the && and || a precedence issue must be addressed: they must
have the highest precedence, witch is not working now:

  1 == 2 || 3 != 2

The or should be the higher level of the tree in the example above.

Signed-off-by: Carlos Maniero <carlos@maniero.me>

1 files changed, 13 insertions, 3 deletions

diff --git a/examples/if.pipa b/examples/if.pipa
index 2c5578d..b7cadcb 100644
--- a/examples/if.pipa
+++ b/examples/if.pipa
@@ -1,8 +1,18 @@
 fn main(): i32 {
-  let n: i32 = 42;
+  let n: i32 = 11;
 
-  if n > 42 {
-    return 42;
+  if (n == 11) {
+    if n != 12 {
+      if n < 12 {
+        if n <= 11 {
+          if n > 10 {
+            if n >= 11 {
+              return 42;
+            }
+          }
+        }
+      }
+    }
   }
 
   return n;