import JSON
json = """{"a": 1, "b": null, "c": [1, 2, 3]}"""
j = JSON.parse(json)
struct MyType
a::Int
b::Union{Nothing, String}
c::Vector{Int}
end
j = JSON.parse(json, MyType)
# ERROR: MethodError: no method matching parse(::String, ::Type{MyType})
# The function `parse` exists, but no method is defined for this combination of argument types.
#
# Closest candidates are:
# parse(::AbstractString; dicttype, inttype, allownan, null)
# @ JSON ~/.julia/packages/JSON/93Ea8/src/Parser.jl:443
# parse(::IO; dicttype, inttype, allownan, null)
# @ JSON ~/.julia/packages/JSON/93Ea8/src/Parser.jl:474
(jl_lnuQYN) pkg> st
Status `/private/var/folders/4n/gvbmlhdc8xj973001s6vdyw00000gq/T/jl_lnuQYN/Project.toml`
[682c06a0] JSON v1.4.0
julia> versioninfo()
Julia Version 1.11.7
Commit f2b3dbda30a (2025-09-08 12:10 UTC)
Build Info:
Official https://julialang.org/ release
Platform Info:
OS: macOS (x86_64-apple-darwin24.0.0)
CPU: 12 × Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz
WORD_SIZE: 64
LLVM: libLLVM-16.0.6 (ORCJIT, skylake)
Threads: 12 default, 0 interactive, 6 GC (on 12 virtual cores)
Environment:
JULIA_LTS_PATH = /Applications/Julia-1.10.app/Contents/Resources/julia/bin/julia
JULIA_PATH = /Users/anthony/.juliaup/bin/julia
JULIA_EGLOT_PATH = /Applications/Julia-1.7.app/Contents/Resources/julia/bin/julia
JULIA_NUM_THREADS = 12
JULIA_NIGHTLY_PATH = /Applications/Julia-1.11.app/Contents/Resources/julia/bin/julia
JULIA_PKG_SERVER = pumasai.juliahub.com
