refactor: rename `mingling_picker` to `arg_picker`

1 files changed, 315 insertions, 0 deletions

diff --git a/arg_picker_macros/src/internal_repeat.rs b/arg_picker_macros/src/internal_repeat.rs
new file mode 100644
index 0000000..4b2242b
--- /dev/null
+++ b/arg_picker_macros/src/internal_repeat.rs
@@ -0,0 +1,315 @@
+use proc_macro::{Delimiter, Group, Ident, Literal, TokenStream, TokenTree};
+
+pub(crate) fn internal_repeat(input: TokenStream) -> TokenStream {
+    let tokens: Vec<TokenTree> = input.into_iter().collect();
+    let (range_start, range_end, body_start) = parse_range(&tokens);
+
+    let mut body: Vec<TokenTree> = tokens[body_start..].to_vec();
+    if body.len() == 1
+        && let TokenTree::Group(g) = &body[0]
+        && g.delimiter() == Delimiter::Brace
+    {
+        body = g.stream().into_iter().collect();
+    }
+
+    let mut result = Vec::new();
+    for i in range_start..=range_end {
+        result.extend(expand_body(&body, i, range_start, range_end));
+    }
+    result.into_iter().collect()
+}
+
+/// Parse `start .. end =>` or `start ..= end =>` or `count =>` (backward compat).
+/// Returns `(start, end_inclusive, body_start_index)`.
+fn parse_range(tokens: &[TokenTree]) -> (usize, usize, usize) {
+    // Find => separator
+    let arrow_pos = tokens.windows(2).position(|w| {
+        matches!(&w[0], TokenTree::Punct(p) if p.as_char() == '=')
+            && matches!(&w[1], TokenTree::Punct(p) if p.as_char() == '>')
+    });
+
+    let (arrow_pos, body_start) = match arrow_pos {
+        Some(p) => (p, p + 2),
+        None => return (1, 12, 0), // fallback
+    };
+
+    let before: Vec<&TokenTree> = tokens[..arrow_pos].iter().collect();
+
+    // Try to find `..` or `..=` pattern
+    // `..` is two Punct('.') tokens
+    let dotdot = before.windows(2).position(|w| {
+        matches!(w[0], TokenTree::Punct(p) if p.as_char() == '.')
+            && matches!(w[1], TokenTree::Punct(p) if p.as_char() == '.')
+    });
+
+    if let Some(dd) = dotdot {
+        // Start value: tokens before `..`
+        let start = parse_usize_tokens(&before[..dd]);
+        let after_dd = &before[dd + 2..];
+
+        // Check for `..=` (inclusive range)
+        let (inclusive, end_tokens) = if after_dd
+            .first()
+            .is_some_and(|t| matches!(t, TokenTree::Punct(p) if p.as_char() == '='))
+        {
+            (true, &after_dd[1..])
+        } else {
+            (false, after_dd)
+        };
+
+        let end = parse_usize_tokens(end_tokens);
+
+        if inclusive {
+            (start, end, body_start)
+        } else {
+            // Exclusive end: if end >= start, iterate start..end, so end_inclusive = end - 1
+            if end > start {
+                (start, end - 1, body_start)
+            } else {
+                (1, 12, body_start) // fallback
+            }
+        }
+    } else {
+        // No `..` found — fallback to simple count
+        let count = parse_usize_tokens(&before);
+        (1, count, body_start)
+    }
+}
+
+/// Parse a sequence of tokens as a single usize value.
+fn parse_usize_tokens(tokens: &[&TokenTree]) -> usize {
+    let s: String = tokens
+        .iter()
+        .map(|t| match t {
+            TokenTree::Literal(l) => l.to_string(),
+            TokenTree::Ident(id) => id.to_string(),
+            _ => String::new(),
+        })
+        .collect::<Vec<_>>()
+        .join("")
+        .replace(' ', "");
+
+    s.parse().unwrap_or(12)
+}
+
+/// Walk tokens, replacing:
+///   `$`   → current
+///   `^$`  → max
+///   `$^`  → min
+///   `$+`  → current + 1 (clamped)
+///   `$-`  → current - 1 (clamped)
+///   `ident$` → ident{current}
+/// and expanding `( … )+` / `( … ,)+` / `( … ;)+` groups.
+fn expand_body(tokens: &[TokenTree], current: usize, min: usize, max: usize) -> Vec<TokenTree> {
+    let mut out = Vec::new();
+    let mut i = 0;
+    while i < tokens.len() {
+        // Check for a parenthesized repetition group: ( ... ) sep? +
+        if let Some(exp) = try_expand_paren_group(tokens, i, current, min, max) {
+            let (items, consumed) = exp;
+            out.extend(items);
+            i += consumed;
+            continue;
+        }
+
+        // `^$` — max value
+        if let TokenTree::Punct(p) = &tokens[i]
+            && p.as_char() == '^'
+            && i + 1 < tokens.len()
+            && let TokenTree::Punct(p2) = &tokens[i + 1]
+            && p2.as_char() == '$'
+        {
+            out.push(TokenTree::Literal(Literal::usize_suffixed(max)));
+            i += 2;
+            continue;
+        }
+
+        // `ident$` / `ident$+` / `ident$-` / `ident$^`
+        // → {ident}{current} / {ident}{current+1} / {ident}{current-1} / {ident}{min}
+        if let TokenTree::Ident(id) = &tokens[i] {
+            if i + 1 < tokens.len()
+                && let TokenTree::Punct(p) = &tokens[i + 1]
+                && p.as_char() == '$'
+            {
+                // Check for ident$+ / ident$- / ident$^
+                if i + 2 < tokens.len() {
+                    match &tokens[i + 2] {
+                        TokenTree::Punct(p2) if p2.as_char() == '+' => {
+                            // ident$+ → {ident}{current+1}
+                            let name = format!("{}{}", id, current + 1);
+                            out.push(TokenTree::Ident(Ident::new(&name, id.span())));
+                            i += 3;
+                            continue;
+                        }
+                        TokenTree::Punct(p2) if p2.as_char() == '-' => {
+                            // ident$- → {ident}{current-1}
+                            let val = current.saturating_sub(1);
+                            let name = format!("{}{}", id, val);
+                            out.push(TokenTree::Ident(Ident::new(&name, id.span())));
+                            i += 3;
+                            continue;
+                        }
+                        TokenTree::Punct(p2) if p2.as_char() == '^' => {
+                            let name = format!("{}{}", id, min);
+                            out.push(TokenTree::Ident(Ident::new(&name, id.span())));
+                            i += 3;
+                            continue;
+                        }
+                        _ => {}
+                    }
+                }
+                // ident$ alone → {ident}{current}
+                let name = format!("{}{}", id, current);
+                out.push(TokenTree::Ident(Ident::new(&name, id.span())));
+                i += 2;
+                continue;
+            }
+            out.push(tokens[i].clone());
+            i += 1;
+            continue;
+        }
+
+        match &tokens[i] {
+            TokenTree::Punct(p) if p.as_char() == '$' => {
+                // lookahead for $^, $+, $-
+                if i + 1 < tokens.len() {
+                    match &tokens[i + 1] {
+                        TokenTree::Punct(p2) if p2.as_char() == '^' => {
+                            // $^ → min
+                            out.push(TokenTree::Literal(Literal::usize_suffixed(min)));
+                            i += 2;
+                            continue;
+                        }
+                        TokenTree::Punct(p2) if p2.as_char() == '+' => {
+                            // $+ → current + 1
+                            out.push(TokenTree::Literal(Literal::usize_suffixed(current + 1)));
+                            i += 2;
+                            continue;
+                        }
+                        TokenTree::Punct(p2) if p2.as_char() == '-' => {
+                            // $- → current - 1
+                            let val = current.saturating_sub(1);
+                            out.push(TokenTree::Literal(Literal::usize_suffixed(val)));
+                            i += 2;
+                            continue;
+                        }
+                        _ => {}
+                    }
+                }
+                // `$` alone → current
+                out.push(TokenTree::Literal(Literal::usize_suffixed(current)));
+                i += 1;
+                continue;
+            }
+            TokenTree::Group(g) => {
+                let inner = expand_body_vec(&g.stream(), current, min, max);
+                out.push(TokenTree::Group(Group::new(
+                    g.delimiter(),
+                    inner.into_iter().collect(),
+                )));
+            }
+            other => out.push(other.clone()),
+        }
+        i += 1;
+    }
+    out
+}
+
+fn expand_body_vec(stream: &TokenStream, current: usize, min: usize, max: usize) -> Vec<TokenTree> {
+    let v: Vec<TokenTree> = stream.clone().into_iter().collect();
+    expand_body(&v, current, min, max)
+}
+
+/// Try to expand a repetition group.
+///
+/// New syntax (repetition marker `+` is the LAST token INSIDE the parens):
+/// - `(group,+)`    — repeat `*` times (current), `,` is the separator
+/// - `(group,+)`    — repeat `*` times, `,` is the separator
+/// - `(group,+)`    — repeat `*` times, `;` is the separator
+/// - `(group +)`    — repeat `*` times, no separator
+/// - `(group,+)+`   — repeat `*+1` times (with separator)
+/// - `(group,+)--`   — repeat `*-1` times (with separator) [not yet used]
+///
+/// The `*` is the current counter value. An optional `+` or `-` immediately
+/// after the closing paren shifts the repeat count up or down by one.
+fn try_expand_paren_group(
+    tokens: &[TokenTree],
+    i: usize,
+    current: usize,
+    _min: usize,
+    _max: usize,
+) -> Option<(Vec<TokenTree>, usize)> {
+    let group = match tokens.get(i)? {
+        TokenTree::Group(g) if g.delimiter() == Delimiter::Parenthesis => g,
+        _ => return None,
+    };
+
+    let stream: Vec<TokenTree> = group.stream().into_iter().collect();
+
+    // Repetition syntax: the LAST token inside the parens MUST be `+`.
+    //   `(content,+)`      — repeat * times, `,` separator
+    //   `(content;+)`      — repeat * times, `;` separator
+    //   `(content,+)`      — repeat * times, no separator
+    //   `(content,+)+`     — repeat *+1 times
+    //   `(content,+)-`     — repeat *-1 times
+    // An optional `+` / `-` right after `)` shifts the count by ±1.
+    //
+    // Any `+` tokens inside `content` are treated as regular Rust syntax
+    // (trait bounds, etc.) — the repetition marker is ONLY the final `+`.
+
+    let last_is_plus = stream
+        .last()
+        .is_some_and(|t| matches!(t, TokenTree::Punct(p) if p.as_char() == '+'));
+    if !last_is_plus {
+        return None;
+    }
+
+    // Determine separator and inner content.
+    let (inner, sep_str): (Vec<TokenTree>, &str) = {
+        if stream.len() >= 2 {
+            let sep_idx = stream.len() - 2;
+            match &stream[sep_idx] {
+                TokenTree::Punct(p) if p.as_char() == ',' => {
+                    // (...,content,+) — inner is everything before the last `,`
+                    let content: Vec<TokenTree> = stream[..sep_idx].into();
+                    (content, ",")
+                }
+                TokenTree::Punct(p) if p.as_char() == ';' => {
+                    let content: Vec<TokenTree> = stream[..sep_idx].into();
+                    (content, ";")
+                }
+                _ => {
+                    // (content+) — no separator, the `+` is the only special token
+                    let content: Vec<TokenTree> = stream[..stream.len() - 1].into();
+                    (content, "")
+                }
+            }
+        } else {
+            // (+) — bare repetition marker, empty content
+            (vec![], "")
+        }
+    };
+
+    // Handle modifier after `)`
+    let rest = &tokens[i + 1..];
+    let modifier: isize = match rest.first() {
+        Some(TokenTree::Punct(p)) if p.as_char() == '+' => 1,
+        Some(TokenTree::Punct(p)) if p.as_char() == '-' => -1,
+        _ => 0,
+    };
+    let consumed = if modifier != 0 { 2 } else { 1 };
+    let repeat_count = (current as isize + modifier) as usize;
+
+    let mut out = Vec::new();
+    for n in 1..=repeat_count {
+        if n > 1 && !sep_str.is_empty() {
+            out.push(TokenTree::Punct(proc_macro::Punct::new(
+                sep_str.chars().next().unwrap(),
+                proc_macro::Spacing::Alone,
+            )));
+        }
+        out.extend(expand_body(&inner, n, 1, repeat_count));
+    }
+
+    Some((out, consumed))
+}