[denzquix]

It bugs me that the numerical for-loop in Terra has identical syntax to Lua's, but different semantics. Especially since you are encouraged to mix Lua and Terra code in the same file. Even something like:

for i = 0, < 10 do --[[ ... ]] end

...and throwing a compile error if you omit the <, though arguably ugly and weird, would still have been preferable I think.

[omaranto]

I couldn't find a description of the Terra for loop in a few minutes of poking through the website and the paper. How is it different from the numeric Lua for loop?

[tekacs]

From http://terralang.org/getting-started.html#control_flow

     Terra also includes for loop. This example counts from 0 up to but not including 10:  
       
     for i = 0,10 do  
         C.printf("%d\n",i)  
     end  
       
     This is different from Lua’s behavior (which is inclusive of 10) since Terra uses 0-based indexing and pointer arithmetic in contrast with Lua’s 1-based indexing. Ideally, Lua and Terra would use the same indexing rules. However, Terra code needs to frequently do pointer arithmetic and interface with C code both of which are cumbersome with 1-based indexing. Alternatively, patching Lua to make it 0-based would make the flavor of Lua bundled with Terra incompatible with existing Lua code.  
       
     Lua also has a for loop that operates using iterators. This is not yet implemented (NYI) in Terra, but a version will be added eventually.  
       
     The loop may also specify an option step parameter:  
       
     for i = 0,10,2 do  
         c.printf("%d\n",i) --0, 2, 4, ...  
     end