Yggdrasil
1 program
Added 2026-03-13T10:00:00Z
Agent: claude-codeModel: claude-sonnet-4-6WebSearch: disabled
Evidence
Report issue
View issues
Aliases: YGGDRASIL
Provenance: commit a2f578b442 · authored 2026-03-13T04:57:04+01:00 · agent claude-code · model claude-sonnet-4-6
Sources mentioning this language
2 sources · pl_id:
pl/yggdrasilRelated languages
Real programs from Software Heritage
No SWH evidence indexed yet for this language. (Either the SWH mining hasn't reached this language's extensions, or no matching files exist in the archive.)
Programs collected by LLM agents experimental · unverified
Gathered by LLM agents during the experiment that started this catalogue. They are not verified: the agent names an origin, but a program can be altered or invented — an audit found one attributed to a file that does not exist, in a syntax the language does not have. Prefer the programs archived by Software Heritage above. The catalogue's goal is the languages themselves, grounded in sources (PLDB, Wikipedia, Rosetta Code, …), with real archived programs; these examples may be dropped.
File System Invariant Verification
Provenance: commit a2f578b442 · authored 2026-03-13T04:57:04+01:00 · agent claude-code · model claude-sonnet-4-6 · WebSearch disabled
# Simple file system specification using Yggdrasil
# Yggdrasil: A Machine-Checked Construction of File Systems
# From: https://github.com/uw-unsat/yggdrasil
from z3 import *
# Disk model: array of blocks
BlockSize = 512
NumBlocks = 1024
def make_disk():
return Array('disk', BitVecSort(32), BitVecSort(8 * BlockSize))
def disk_read(disk, blkno):
return disk[blkno]
def disk_write(disk, blkno, data):
return Store(disk, blkno, data)
# File system invariant: superblock is valid
def fs_invariant(disk):
sb = disk_read(disk, BitVecVal(0, 32)) # superblock at block 0
magic = Extract(31, 0, sb) # first 4 bytes are magic number
return magic == BitVecVal(0xDEADBEEF, 32)
# Verify that writes preserve the invariant
def verify_write_preserves_invariant():
disk = make_disk()
blkno = BitVec('blkno', 32)
data = BitVec('data', 8 * BlockSize)
s = Solver()
# Assume invariant holds before write
s.add(fs_invariant(disk))
# Write to non-superblock location
s.add(UGT(blkno, BitVecVal(0, 32)))
new_disk = disk_write(disk, blkno, data)
# Check invariant still holds
s.add(Not(fs_invariant(new_disk)))
result = s.check()
if result == unsat:
print("Verified: writes to non-superblock preserve fs invariant")
else:
print("Counterexample found:", s.model())
if __name__ == '__main__':
verify_write_preserves_invariant()