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feat(zig): native Arboricx bundle parser and C ABI

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This commit is contained in:
James Eversole
2026-05-10 21:21:58 -05:00
parent 8a673e282d
commit d7a7a8134c
27 changed files with 5365 additions and 18 deletions
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128
ext/zig/src/reduce.zig Normal file
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const std = @import("std");
const tree = @import("tree.zig");
const Arena = @import("arena.zig").Arena;
pub const ReduceError = error{
FuelExhausted,
InvalidApply,
OutOfMemory,
};
/// Reduce a term to weak head normal form.
pub fn reduce(root: u32, arena: *Arena, fuel: u64) ReduceError!u32 {
var remaining = fuel;
return try whnf(root, arena, &remaining);
}
fn whnf(term: u32, arena: *Arena, fuel: *u64) ReduceError!u32 {
if (fuel.* == 0) return error.FuelExhausted;
var current = term;
while (true) {
switch (arena.get(current).*) {
.leaf, .stem, .fork => return current,
.app => |app| {
const orig = current;
const func_idx = app.func;
const arg_idx = app.arg;
// Reduce function to WHNF
const f = try whnf(func_idx, arena, fuel);
if (fuel.* == 0) return error.FuelExhausted;
fuel.* -= 1;
switch (arena.get(f).*) {
// apply Leaf b = Stem b
.leaf => {
arena.get(orig).* = .{ .stem = .{ .child = arg_idx } };
return orig;
},
// apply (Stem a) b = Fork a b
.stem => |s| {
const a = s.child;
arena.get(orig).* = .{ .fork = .{ .left = a, .right = arg_idx } };
return orig;
},
.fork => |fork_f| {
const left_idx = fork_f.left;
const right_idx = fork_f.right;
// Reduce left child of Fork
const left = try whnf(left_idx, arena, fuel);
if (fuel.* == 0) return error.FuelExhausted;
fuel.* -= 1;
switch (arena.get(left).*) {
// apply (Fork Leaf a) _ = a
.leaf => {
const result = try whnf(right_idx, arena, fuel);
if (fuel.* == 0) return error.FuelExhausted;
fuel.* -= 1;
if (orig != result) {
arena.get(orig).* = arena.get(result).*;
}
return orig;
},
// apply (Fork (Stem a) b) c = (a c) (b c)
.stem => |s| {
const a = s.child;
const inner1 = try arena.alloc(.{ .app = .{ .func = a, .arg = arg_idx } });
const inner2 = try arena.alloc(.{ .app = .{ .func = right_idx, .arg = arg_idx } });
arena.get(orig).* = .{ .app = .{ .func = inner1, .arg = inner2 } };
current = orig;
if (fuel.* == 0) return error.FuelExhausted;
fuel.* -= 1;
continue;
},
.fork => {
// Reduce argument
const arg = try whnf(arg_idx, arena, fuel);
if (fuel.* == 0) return error.FuelExhausted;
fuel.* -= 1;
switch (arena.get(arg).*) {
// apply (Fork (Fork a b) c) Leaf = a
.leaf => {
const a_idx = arena.get(left).fork.left;
const result = try whnf(a_idx, arena, fuel);
if (fuel.* == 0) return error.FuelExhausted;
fuel.* -= 1;
if (orig != result) {
arena.get(orig).* = arena.get(result).*;
}
return orig;
},
// apply (Fork (Fork a b) c) (Stem u) = b u
.stem => |s| {
const b_idx = arena.get(left).fork.right;
const u = s.child;
arena.get(orig).* = .{ .app = .{ .func = b_idx, .arg = u } };
current = orig;
if (fuel.* == 0) return error.FuelExhausted;
fuel.* -= 1;
continue;
},
// apply (Fork (Fork a b) c) (Fork u v) = (c u) v
.fork => |arg_fork| {
const c_idx = right_idx;
const u = arg_fork.left;
const v = arg_fork.right;
const inner = try arena.alloc(.{ .app = .{ .func = c_idx, .arg = u } });
arena.get(orig).* = .{ .app = .{ .func = inner, .arg = v } };
current = orig;
if (fuel.* == 0) return error.FuelExhausted;
fuel.* -= 1;
continue;
},
.app => return error.InvalidApply,
}
},
.app => return error.InvalidApply,
}
},
.app => return error.InvalidApply,
}
},
}
}
}