Module iter 

Iteration-related Tokel Transformers.

Available Transformers

Transformer	Argument Type	Description
Reverse	syn::parse::Nothing	Reverses the sequence of token trees.
Intersperse	TokenTree	Inserts a token-tree between each token-tree in the input.
PushLeft	TokenStream	Prepends a token stream to the input.
PushRight	TokenStream	Appends a token stream to the input.
PopLeft	syn::parse::Nothing	Removes the first token tree from the stream.
PopRight	syn::parse::Nothing	Removes the last token tree from the stream.
Take	syn::LitInt	Keeps only the first N tokens from the stream.
Skip	syn::LitInt	Discards the first N tokens from the stream.
Repeat	syn::LitInt	Duplicates the input stream N times.
Count	syn::parse::Nothing	Emits the number of token trees present in the stream.
Sequence	SequenceRange	Generates a sequence of integers based on a provided range.

Argument Types

• syn::parse::Nothing: No argument required.
• TokenTree: A single token tree (e.g., a punctuation, identifier, etc.).
• TokenStream: A sequence of token trees.
• syn::LitInt: An integer literal (e.g., [[ 3 ]]).
• SequenceRange: A Rust range literal (e.g., [[ 1..=3 ]]).

Examples

• [< a b c >]:reverse ->c b a
• [< a b c >]:intersperse[[,]] ->a , b , c
• [< b c >]:push_left[[a]] ->a b c
• [< a b c >]:pop_right ->a b
• [< a b c >]:take[[2]] ->a b
• [< a b c >]:skip[[1]] ->b c
• [< a b >]:repeat[[3]] ->a b a b a b
• [< a b c >]:count ->3
• [< >]:sequence[[ 1..=3 ]] ->1 2 3

• Transformers can be nested or composed by evaluating other transformers inside arguments:

• [< a b c >]:intersperse[[[< x y >]:reverse]] ->a y x b y x c
• [< a b c >]:push_left[[[< x y >]:reverse]] ->y x a b c
• [< a b c >]:push_right[[[< d e >]:take[[1]]]] ->a b c d
• [< 1 2 3 >]:take[[[< 2 1 >]:reverse:take[[1]]]] ->1 2
• [< a b c >]:repeat[[[< 2 1 >]:count]] ->a b c a b c
• [< >]:sequence[[[< 1 4 >]:reverse:take[[1]]..4]] ->3 4 5 6

Structs

Count

Emits the number of token trees present in the stream.

Intersperse

Inserts the provided token-tree in between each token-tree in the input.

PopLeft

Removes the first token tree from the stream.

PopRight

Removes the last token tree from the stream (useful for trailing commas or other garbage).

PushLeft

Pushes the provided token stream to the start (left) of the input token stream.

PushRight

Appends the provided token stream to the end (right) of the input token stream.

Repeat

Duplicates the input stream N times.

Reverse

Reverses the sequence of token trees in the stream.

Sequence

Generates a sequence of integers based on a provided range.

Skip

Discards the first N tokens from the stream.

Take

Keeps only the first N tokens from the stream.

Enums

SequenceRange

The range argument of a Sequence pass.

Functions

register

Inserts all iter-related Transformers into the specified Registry.