If it was something that is hardly ever hand-written then it might be Ok

Problem with making null Unicode was that it comes up a lot (albeit less in k9 eg because cut now has I^ for greedy take)

@yiyus lambdas in x,y,z are common in some contexts, rare in others. for example, when writing for a limited audience of k experts i prefer very short names and very compact code. when writing as part of a larger team with a large and complex code-base, i will use longer descriptive names (for the functions, not the locals) and an explicit argument list. and in that case i will adopt a style of short lines with at most a single assignment -- a:...

@ktye one or more recursive combinators, as developed by john earnest and i and presented in his vector paper of a few years ago.

regarding how to map single symbolic characters to useful array ops, matters get simpler when designing a purely concatenative language on the model of Joy, or the even simpler language False. if you have any interest in this topic you can study the assignments i make in the two false-like languages F and G here: nsl.com/k/f/f.htm, especially section 9.

@StevanApter thanks! I was asking specifically about expressions like :x+y, not functions like {x+y}. Is that what you meant?

@ngn tring to port ngn/k to macos with nostdlib. now get only one test case left. n:#1:"t.k";(0<n)&n<10000000. which gives 'mmap1 error. i looked at the implementation of 1: what's the two-step mmap for? i don't i have enough knowledge to debug this...

in addition, allocations are not allowed beween the two steps (this is asserted in debug mode)

the purpose is to make memory access more sequential - the refcount is in the header, so better deal with it first instead "going back" after the vector's data is processed

oops.. ignore the above - that was about the two-step free()

@ksi the two-step mmap() works like this: the first call to mmap allocates memory for the array + 1 additional page. the additional page is for the header. even though the header is just 16 bytes, it must take a whole page, because mmap() can only work on page-aligned addresses.

the second mmap() puts the file content within the memory allocated by the first mmap(), leaving out the first page

did i explain it well enough? i'm not good at this.. i'll try to draw a diagram

    |       |       |       |       |       |
    |    hdr|content,content,content..      |
     \_____/
     1 page=4096 bytes

    ^       ^
    |       |
    |       second mmap is MAP_FIXED at this address
    |        and it puts file content there
    |
    first mmap returns this address as MAP_ANONYMOUS memory

@ngn i think i got you, so we should expect the second mmap() return the same pointer as ZP+p, if the file is correctly mapped to that chunk of memory. so, error probably means the file is mapped to somewhere else or maybe error happened.

@ksi correct. unfortunately i don't have access to a mac to test on.

@ngn i am not sure how mmap works, why wouldn't the first mmap marks the whole chunk of memory taken, so the second mmap has to find another page?

@ksi i'm not sure what you mean. could you rephrase the question?

the first mmap makes sure there's enough room for header+content. the second mmap "fills in" the actual content. i don't think i can get away with a single mmap.

@ngn i thought mmap is used to allocate a new chunk of memory, is this true only when the second last parameter is -1?

@ksi it's used for both: allocating memory (with MAP_ANONYMOUS and fd==-1) and mapping files (with fd!=-1)

u1c() reads from a file ma() allocates normal memory

not the first time this comes up in k-land: github.com/kevinlawler/kona/issues/162

@ngn okay i will look more into this. another strange thing is when i change the optimization flag from O0 to O3, three more json parser test cases fails, although i manually checked and found the results are correct.

@ksi huh. that's strange.

@ktye I'd get rid of the overloads and promote function take and function drop to a bonafide adverb called filter instead of using overloads of # and _ which are verbs

@richie in apl/iv i experimented with functions within bracket indexing. see the last examples of github.com/ktye/iv/blob/master/TESTS.md#indexing-tables

offtopic: lol, i feel surrounded :)