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diff --git a/archive/2021-11-09-ascii-parser-aborted-idea b/archive/2021-11-09-ascii-parser-aborted-idea new file mode 100644 index 0000000..765976c --- /dev/null +++ b/archive/2021-11-09-ascii-parser-aborted-idea @@ -0,0 +1,60 @@ +Background +--- +Is it possible to make our ascii parser simpler and less error-prone for lists? + +Suppose we have a list of items named "apples". Each item contains a single value. +The list apples=[v1,v2] would be expressed as follows: +``` +apples=v1 +...possibly other key-value pairs... +apples=v2 +``` + +Suppose we have a list of items named "fruits". Each fruit item contains two values +for the fields "apple" and "banana". The list fruits=[(apple=v1,banana=v2), (apple=v3,banana=v4)] could be expressed as follows: +``` +banana=v2 +apple=v1 +apple=v3 +banana=v4 +``` + +To parse this successfully, we require that the number of apple lines are the same as +the number of banana lines. Then we join apple-banana pairs in the observed ordered, +i.e., the first apple line is associated with the first banana line, etc. + +Observation +--- +Would it be simpler to parse the following: + +``` +fruits=apple-->v1; banana-->v2; +fruits=banana-->v4; apple-->v3; +``` + +In other words, the list is identified by a key. An item's key-value pairs are listed +on the same line, and uses _the same ASCII parser but with different delimitors_. + +To improve readability for humans, the delimiting pattern could be based on k, k-1, +k-2,...,1 new lines. The same technique could be used for the end-of-key pattern. +``` +key==key1=v1 +key2=v3 + +key==key1=v2 +key2=v4 + +``` + +Discussion +--- +Not convinced that nested parsers are simpler than joining lists after checking that +all sizes match. It might be easier to look at for humans, because we get each item +grouped in the same place. Our parser description would become more complex, however. + +Assuming that the parser's syntax is understood, it might be the case that it is easier +to implement generally in a high-level language. That is a non-goal though. + +Conclusion +--- +This idea does not seem to be simpler and less error-prone in general. Abort! |