Extract pest_consume into its own crate

4 files changed, 0 insertions, 718 deletions

diff --git a/pest_consume_macros/Cargo.toml b/pest_consume_macros/Cargo.toml
deleted file mode 100644
index aaa0b10..0000000
--- a/pest_consume_macros/Cargo.toml
+++ /dev/null
@@ -1,19 +0,0 @@
-[package]
-name = "pest_consume_macros"
-version = "0.1.0"  # remember to update html_root_url
-authors = ["Nadrieril <nadrieril@users.noreply.github.com>"]
-license = "MIT OR Apache-2.0"
-edition = "2018"
-description = "Macros for pest_consume"
-readme = "README.md"
-repository = "https://github.com/Nadrieril/dhall-rust"
-
-[lib]
-proc-macro = true
-doctest = false
-
-[dependencies]
-quote = "1.0.2"
-proc-macro2 = "1.0.2"
-proc-macro-hack = "0.5.9"
-syn = { version = "1.0.5", features = ["full"] }
diff --git a/pest_consume_macros/src/lib.rs b/pest_consume_macros/src/lib.rs
deleted file mode 100644
index d726b5d..0000000
--- a/pest_consume_macros/src/lib.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-//! This crate contains the code-generation primitives for the [dhall-rust][dhall-rust] crate.
-//! This is highly unstable and breaks regularly; use at your own risk.
-//!
-//! [dhall-rust]: https://github.com/Nadrieril/dhall-rust
-
-extern crate proc_macro;
-
-mod make_parser;
-mod match_nodes;
-
-use proc_macro::TokenStream;
-
-#[proc_macro_attribute]
-pub fn parser(attrs: TokenStream, input: TokenStream) -> TokenStream {
-    TokenStream::from(match make_parser::make_parser(attrs, input) {
-        Ok(tokens) => tokens,
-        Err(err) => err.to_compile_error(),
-    })
-}
-
-#[proc_macro_hack::proc_macro_hack]
-pub fn match_nodes(input: TokenStream) -> TokenStream {
-    TokenStream::from(match match_nodes::match_nodes(input) {
-        Ok(tokens) => tokens,
-        Err(err) => err.to_compile_error(),
-    })
-}
diff --git a/pest_consume_macros/src/make_parser.rs b/pest_consume_macros/src/make_parser.rs
deleted file mode 100644
index 5bf8fe3..0000000
--- a/pest_consume_macros/src/make_parser.rs
+++ /dev/null
@@ -1,424 +0,0 @@
-use std::collections::HashMap;
-use std::iter;
-
-use quote::quote;
-use syn::parse::{Parse, ParseStream, Result};
-use syn::spanned::Spanned;
-use syn::{
-    parse_quote, Error, Expr, FnArg, Ident, ImplItem, ImplItemMethod, ItemImpl,
-    LitBool, Pat, Path, Token,
-};
-
-/// Ext. trait adding `partition_filter` to `Vec`. Would like to use `Vec::drain_filter`
-/// but it's unstable for now.
-pub trait VecPartitionFilterExt<Item> {
-    fn partition_filter<F>(&mut self, predicate: F) -> Vec<Item>
-    where
-        F: FnMut(&mut Item) -> bool;
-}
-
-impl<Item> VecPartitionFilterExt<Item> for Vec<Item> {
-    fn partition_filter<F>(&mut self, mut predicate: F) -> Vec<Item>
-    where
-        F: FnMut(&mut Item) -> bool,
-    {
-        let mut ret = Vec::new();
-        let mut i = 0;
-        while i != self.len() {
-            if predicate(&mut self[i]) {
-                ret.push(self.remove(i))
-            } else {
-                i += 1;
-            }
-        }
-        ret
-    }
-}
-
-mod kw {
-    syn::custom_keyword!(shortcut);
-    syn::custom_keyword!(rule);
-    syn::custom_keyword!(parser);
-}
-
-struct MakeParserAttrs {
-    parser: Path,
-    rule_enum: Path,
-}
-
-struct AliasArgs {
-    target: Ident,
-    is_shortcut: bool,
-}
-
-struct PrecClimbArgs {
-    child_rule: Ident,
-    climber: Expr,
-}
-
-struct AliasSrc {
-    ident: Ident,
-    is_shortcut: bool,
-}
-
-struct ParsedFn<'a> {
-    // Body of the function
-    function: &'a mut ImplItemMethod,
-    // Name of the function.
-    fn_name: Ident,
-    // Name of the first argument of the function, which should be of type `Node`.
-    input_arg: Ident,
-    // List of aliases pointing to this function
-    alias_srcs: Vec<AliasSrc>,
-}
-
-impl Parse for MakeParserAttrs {
-    fn parse(input: ParseStream) -> Result<Self> {
-        // By default, the pest parser is the same type as the pest_consume one
-        let mut parser = parse_quote!(Self);
-        // By default, use the `Rule` type in scope
-        let mut rule_enum = parse_quote!(Rule);
-
-        while !input.is_empty() {
-            let lookahead = input.lookahead1();
-            if lookahead.peek(kw::parser) {
-                let _: kw::parser = input.parse()?;
-                let _: Token![=] = input.parse()?;
-                parser = input.parse()?;
-            } else if lookahead.peek(kw::rule) {
-                let _: kw::rule = input.parse()?;
-                let _: Token![=] = input.parse()?;
-                rule_enum = input.parse()?;
-            } else {
-                return Err(lookahead.error());
-            }
-
-            if input.peek(Token![,]) {
-                let _: Token![,] = input.parse()?;
-            } else {
-                break;
-            }
-        }
-
-        Ok(MakeParserAttrs { parser, rule_enum })
-    }
-}
-
-impl Parse for AliasArgs {
-    fn parse(input: ParseStream) -> Result<Self> {
-        let target = input.parse()?;
-        let is_shortcut = if input.peek(Token![,]) {
-            // #[alias(rule, shortcut = true)]
-            let _: Token![,] = input.parse()?;
-            let _: kw::shortcut = input.parse()?;
-            let _: Token![=] = input.parse()?;
-            let b: LitBool = input.parse()?;
-            b.value
-        } else {
-            // #[alias(rule)]
-            false
-        };
-        Ok(AliasArgs {
-            target,
-            is_shortcut,
-        })
-    }
-}
-
-impl Parse for PrecClimbArgs {
-    fn parse(input: ParseStream) -> Result<Self> {
-        let child_rule = input.parse()?;
-        let _: Token![,] = input.parse()?;
-        let climber = input.parse()?;
-        Ok(PrecClimbArgs {
-            child_rule,
-            climber,
-        })
-    }
-}
-
-fn collect_aliases(
-    imp: &mut ItemImpl,
-) -> Result<HashMap<Ident, Vec<AliasSrc>>> {
-    let functions = imp.items.iter_mut().flat_map(|item| match item {
-        ImplItem::Method(m) => Some(m),
-        _ => None,
-    });
-
-    let mut alias_map = HashMap::new();
-    for function in functions {
-        let fn_name = function.sig.ident.clone();
-        let mut alias_attrs = function
-            .attrs
-            .partition_filter(|attr| attr.path.is_ident("alias"))
-            .into_iter();
-
-        if let Some(attr) = alias_attrs.next() {
-            let args: AliasArgs = attr.parse_args()?;
-            alias_map.entry(args.target).or_insert_with(Vec::new).push(
-                AliasSrc {
-                    ident: fn_name,
-                    is_shortcut: args.is_shortcut,
-                },
-            );
-        } else {
-            // Self entry
-            alias_map
-                .entry(fn_name.clone())
-                .or_insert_with(Vec::new)
-                .push(AliasSrc {
-                    ident: fn_name,
-                    is_shortcut: false,
-                });
-        }
-        if let Some(attr) = alias_attrs.next() {
-            return Err(Error::new(
-                attr.span(),
-                "expected at most one alias attribute",
-            ));
-        }
-    }
-
-    Ok(alias_map)
-}
-
-fn parse_fn<'a>(
-    function: &'a mut ImplItemMethod,
-    alias_map: &mut HashMap<Ident, Vec<AliasSrc>>,
-) -> Result<ParsedFn<'a>> {
-    let fn_name = function.sig.ident.clone();
-    // Get the name of the first (`input`) function argument
-    let input_arg = function.sig.inputs.first().ok_or_else(|| {
-        Error::new(
-            function.sig.inputs.span(),
-            "a rule function needs an `input` argument",
-        )
-    })?;
-    let input_arg = match &input_arg {
-        FnArg::Receiver(_) => return Err(Error::new(
-            input_arg.span(),
-            "a rule function should not have a `self` argument",
-        )),
-        FnArg::Typed(input_arg) => match &*input_arg.pat{
-            Pat::Ident(ident) => ident.ident.clone(),
-            _ => return Err(Error::new(
-                input_arg.span(),
-                "this argument should be a plain identifier instead of a pattern",
-            )),
-        }
-    };
-
-    let alias_srcs = alias_map.remove(&fn_name).unwrap_or_else(Vec::new);
-
-    Ok(ParsedFn {
-        function,
-        fn_name,
-        input_arg,
-        alias_srcs,
-    })
-}
-
-fn apply_special_attrs(f: &mut ParsedFn, rule_enum: &Path) -> Result<()> {
-    let function = &mut *f.function;
-    let fn_name = &f.fn_name;
-    let input_arg = &f.input_arg;
-
-    *function = parse_quote!(
-        #[allow(non_snake_case)]
-        #function
-    );
-
-    // `prec_climb` attr
-    let prec_climb_attrs: Vec<_> = function
-        .attrs
-        .partition_filter(|attr| attr.path.is_ident("prec_climb"));
-
-    if prec_climb_attrs.len() > 1 {
-        return Err(Error::new(
-            prec_climb_attrs[1].span(),
-            "expected at most one prec_climb attribute",
-        ));
-    } else if prec_climb_attrs.is_empty() {
-        // do nothing
-    } else {
-        let attr = prec_climb_attrs.into_iter().next().unwrap();
-        let PrecClimbArgs {
-            child_rule,
-            climber,
-        } = attr.parse_args()?;
-
-        function.block = parse_quote!({
-            #function
-
-            #climber.climb(
-                #input_arg.as_pair().clone().into_inner(),
-                |p| Self::#child_rule(#input_arg.with_pair(p)),
-                |l, op, r| {
-                    #fn_name(#input_arg.clone(), l?, op, r?)
-                },
-            )
-        });
-        // Remove the 3 last arguments to keep only the `input` one
-        function.sig.inputs.pop();
-        function.sig.inputs.pop();
-        function.sig.inputs.pop();
-        // Check that an argument remains
-        function.sig.inputs.first().ok_or_else(|| {
-            Error::new(
-                function.sig.inputs.span(),
-                "a prec_climb function needs 4 arguments",
-            )
-        })?;
-    }
-
-    // `alias` attr
-    // f.alias_srcs has always at least 1 element because it has an entry pointing from itself.
-    if f.alias_srcs.len() > 1 {
-        let aliases = f
-            .alias_srcs
-            .iter()
-            .map(|src| &src.ident)
-            .filter(|i| i != &fn_name);
-        let block = &function.block;
-        let self_ty = quote!(<Self as ::pest_consume::Parser>);
-        function.block = parse_quote!({
-            let mut #input_arg = #input_arg;
-            // While the current rule allows shortcutting, and there is a single child, and the
-            // child can still be parsed by the current function, then skip to that child.
-            while #self_ty::allows_shortcut(#input_arg.as_rule()) {
-                if let ::std::option::Option::Some(child) = #input_arg.single_child() {
-                    if child.as_aliased_rule::<Self>() == #self_ty::AliasedRule::#fn_name {
-                        #input_arg = child;
-                        continue;
-                    }
-                }
-                break
-            }
-
-            match #input_arg.as_rule() {
-                #(#rule_enum::#aliases => Self::#aliases(#input_arg),)*
-                #rule_enum::#fn_name => #block,
-                r => ::std::unreachable!(
-                    "make_parser: called {} on {:?}",
-                    ::std::stringify!(#fn_name),
-                    r
-                )
-            }
-        });
-    }
-
-    Ok(())
-}
-
-pub fn make_parser(
-    attrs: proc_macro::TokenStream,
-    input: proc_macro::TokenStream,
-) -> Result<proc_macro2::TokenStream> {
-    let attrs: MakeParserAttrs = syn::parse(attrs)?;
-    let parser = &attrs.parser;
-    let rule_enum = &attrs.rule_enum;
-    let mut imp: ItemImpl = syn::parse(input)?;
-
-    let mut alias_map = collect_aliases(&mut imp)?;
-    let rule_alias_branches: Vec<_> = alias_map
-        .iter()
-        .flat_map(|(tgt, srcs)| iter::repeat(tgt).zip(srcs))
-        .map(|(tgt, src)| {
-            let ident = &src.ident;
-            quote!(
-                #rule_enum::#ident => Self::AliasedRule::#tgt,
-            )
-        })
-        .collect();
-    let aliased_rule_variants: Vec<_> =
-        alias_map.iter().map(|(tgt, _)| tgt.clone()).collect();
-    let shortcut_branches: Vec<_> = alias_map
-        .iter()
-        .flat_map(|(_tgt, srcs)| srcs)
-        .map(|AliasSrc { ident, is_shortcut }| {
-            quote!(
-                #rule_enum::#ident => #is_shortcut,
-            )
-        })
-        .collect();
-
-    let fn_map: HashMap<Ident, ParsedFn> = imp
-        .items
-        .iter_mut()
-        .flat_map(|item| match item {
-            ImplItem::Method(m) => Some(m),
-            _ => None,
-        })
-        .map(|method| {
-            let mut f = parse_fn(method, &mut alias_map)?;
-            apply_special_attrs(&mut f, &rule_enum)?;
-            Ok((f.fn_name.clone(), f))
-        })
-        .collect::<Result<_>>()?;
-
-    // Entries that remain in the alias map don't have a matching method, so we create one.
-    let extra_fns: Vec<_> = alias_map
-        .iter()
-        .map(|(tgt, srcs)| {
-            // Get the signature of one of the functions that has this alias. They should all have
-            // essentially the same signature anyways.
-            let f = fn_map.get(&srcs.first().unwrap().ident).unwrap();
-            let input_arg = f.input_arg.clone();
-            let mut sig = f.function.sig.clone();
-            sig.ident = tgt.clone();
-            let srcs = srcs.iter().map(|src| &src.ident);
-
-            Ok(parse_quote!(
-                #sig {
-                    match #input_arg.as_rule() {
-                        #(#rule_enum::#srcs => Self::#srcs(#input_arg),)*
-                        // We can't match on #rule_enum::#tgt since `tgt` might be an arbitrary
-                        // identifier.
-                        r if &::std::format!("{:?}", r) == ::std::stringify!(#tgt) =>
-                            return ::std::result::Result::Err(#input_arg.error(::std::format!(
-                                "make_parser: missing method for rule {}",
-                                ::std::stringify!(#tgt),
-                            ))),
-                        r => ::std::unreachable!(
-                            "make_parser: called {} on {:?}",
-                            ::std::stringify!(#tgt),
-                            r
-                        )
-                    }
-                }
-            ))
-        })
-        .collect::<Result<_>>()?;
-    imp.items.extend(extra_fns);
-
-    let ty = &imp.self_ty;
-    let (impl_generics, _, where_clause) = imp.generics.split_for_impl();
-    Ok(quote!(
-        #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-        #[allow(non_camel_case_types)]
-        enum AliasedRule {
-            #(#aliased_rule_variants,)*
-        }
-
-        impl #impl_generics ::pest_consume::Parser for #ty #where_clause {
-            type Rule = #rule_enum;
-            type AliasedRule = AliasedRule;
-            type Parser = #parser;
-            fn rule_alias(rule: Self::Rule) -> Self::AliasedRule {
-                match rule {
-                    #(#rule_alias_branches)*
-                    // TODO: return a proper error ?
-                    r => ::std::unreachable!("Rule {:?} does not have a corresponding parsing method", r),
-                }
-            }
-            fn allows_shortcut(rule: Self::Rule) -> bool {
-                match rule {
-                    #(#shortcut_branches)*
-                    _ => false,
-                }
-            }
-        }
-
-        #imp
-    ))
-}
diff --git a/pest_consume_macros/src/match_nodes.rs b/pest_consume_macros/src/match_nodes.rs
deleted file mode 100644
index a91d1f4..0000000
--- a/pest_consume_macros/src/match_nodes.rs
+++ /dev/null
@@ -1,248 +0,0 @@
-use proc_macro2::{Span, TokenStream};
-use quote::quote;
-use syn::parse::{Parse, ParseStream, Result};
-use syn::punctuated::Punctuated;
-use syn::spanned::Spanned;
-use syn::{
-    bracketed, parenthesized, parse_quote, token, Error, Expr, Ident, Pat,
-    Token, Type,
-};
-
-#[derive(Clone)]
-struct MatchBranch {
-    // Patterns all have the form [a, b, c.., d], with a bunch of simple patterns,
-    // optionally a multiple pattern, and then some more simple patterns.
-    singles_before_multiple: Vec<(Ident, Pat)>,
-    multiple: Option<(Ident, Ident)>,
-    singles_after_multiple: Vec<(Ident, Pat)>,
-
-    body: Expr,
-}
-
-#[derive(Clone)]
-enum MatchBranchPatternItem {
-    Single {
-        rule_name: Ident,
-        binder: Pat,
-    },
-    Multiple {
-        rule_name: Ident,
-        binder: Ident,
-        slice_token: Token![..],
-    },
-}
-
-#[derive(Clone)]
-struct MacroInput {
-    parser: Type,
-    input_expr: Expr,
-    branches: Punctuated<MatchBranch, Token![,]>,
-}
-
-impl Parse for MatchBranch {
-    fn parse(input: ParseStream) -> Result<Self> {
-        let contents;
-        let _: token::Bracket = bracketed!(contents in input);
-
-        let pattern: Punctuated<MatchBranchPatternItem, Token![,]> =
-            Punctuated::parse_terminated(&contents)?;
-        use MatchBranchPatternItem::{Multiple, Single};
-        let mut singles_before_multiple = Vec::new();
-        let mut multiple = None;
-        let mut singles_after_multiple = Vec::new();
-        for item in pattern.clone() {
-            match item {
-                Single { rule_name, binder } => {
-                    if multiple.is_none() {
-                        singles_before_multiple.push((rule_name, binder))
-                    } else {
-                        singles_after_multiple.push((rule_name, binder))
-                    }
-                }
-                Multiple {
-                    rule_name,
-                    binder,
-                    slice_token,
-                } => {
-                    if multiple.is_none() {
-                        multiple = Some((rule_name, binder))
-                    } else {
-                        return Err(Error::new(
-                            slice_token.span(),
-                            "multiple variable-length patterns are not allowed",
-                        ));
-                    }
-                }
-            }
-        }
-
-        let _: Token![=>] = input.parse()?;
-        let body = input.parse()?;
-
-        Ok(MatchBranch {
-            singles_before_multiple,
-            multiple,
-            singles_after_multiple,
-            body,
-        })
-    }
-}
-
-impl Parse for MatchBranchPatternItem {
-    fn parse(input: ParseStream) -> Result<Self> {
-        let contents;
-        let rule_name = input.parse()?;
-        parenthesized!(contents in input);
-        if input.peek(Token![..]) {
-            let binder = contents.parse()?;
-            let slice_token = input.parse()?;
-            Ok(MatchBranchPatternItem::Multiple {
-                rule_name,
-                binder,
-                slice_token,
-            })
-        } else if input.is_empty() || input.peek(Token![,]) {
-            let binder = contents.parse()?;
-            Ok(MatchBranchPatternItem::Single { rule_name, binder })
-        } else {
-            Err(input.error("expected `..` or nothing"))
-        }
-    }
-}
-
-impl Parse for MacroInput {
-    fn parse(input: ParseStream) -> Result<Self> {
-        let parser = if input.peek(token::Lt) {
-            let _: token::Lt = input.parse()?;
-            let parser = input.parse()?;
-            let _: token::Gt = input.parse()?;
-            let _: Token![;] = input.parse()?;
-            parser
-        } else {
-            parse_quote!(Self)
-        };
-        let input_expr = input.parse()?;
-        let _: Token![;] = input.parse()?;
-        let branches = Punctuated::parse_terminated(input)?;
-
-        Ok(MacroInput {
-            parser,
-            input_expr,
-            branches,
-        })
-    }
-}
-
-fn make_branch(
-    branch: &MatchBranch,
-    i_nodes: &Ident,
-    i_node_rules: &Ident,
-    parser: &Type,
-) -> Result<TokenStream> {
-    let aliased_rule = quote!(<#parser as ::pest_consume::Parser>::AliasedRule);
-
-    // Find which branch to take
-    let mut conditions = Vec::new();
-    let start = branch.singles_before_multiple.len();
-    let end = branch.singles_after_multiple.len();
-    conditions.push(quote!(
-        #start + #end <= #i_node_rules.len()
-    ));
-    for (i, (rule_name, _)) in branch.singles_before_multiple.iter().enumerate()
-    {
-        conditions.push(quote!(
-            #i_node_rules[#i] == #aliased_rule::#rule_name
-        ))
-    }
-    for (i, (rule_name, _)) in branch.singles_after_multiple.iter().enumerate()
-    {
-        conditions.push(quote!(
-            #i_node_rules[#i_node_rules.len()-1 - #i] == #aliased_rule::#rule_name
-        ))
-    }
-    if let Some((rule_name, _)) = &branch.multiple {
-        conditions.push(quote!(
-            {
-                // We can't use .all() directly in the pattern guard; see
-                // https://github.com/rust-lang/rust/issues/59803.
-                let all_match = |slice: &[_]| {
-                    slice.iter().all(|r|
-                        *r == #aliased_rule::#rule_name
-                    )
-                };
-                all_match(&#i_node_rules[#start..#i_node_rules.len() - #end])
-            }
-        ))
-    } else {
-        // No variable-length pattern, so the size must be exactly the number of patterns
-        conditions.push(quote!(
-            #start + #end == #i_node_rules.len()
-        ))
-    }
-
-    // Once we have found a branch that matches, we need to parse the nodes.
-    let mut parses = Vec::new();
-    for (rule_name, binder) in branch.singles_before_multiple.iter() {
-        parses.push(quote!(
-            let #binder = #parser::#rule_name(
-                #i_nodes.next().unwrap()
-            )?;
-        ))
-    }
-    // Note the `rev()`: we are taking nodes from the end of the iterator in reverse order, so that
-    // only the unmatched nodes are left in the iterator for the variable-length pattern, if any.
-    for (rule_name, binder) in branch.singles_after_multiple.iter().rev() {
-        parses.push(quote!(
-            let #binder = #parser::#rule_name(
-                #i_nodes.next_back().unwrap()
-            )?;
-        ))
-    }
-    if let Some((rule_name, binder)) = &branch.multiple {
-        parses.push(quote!(
-            let #binder = #i_nodes
-                .map(|i| #parser::#rule_name(i))
-                .collect::<::std::result::Result<::std::vec::Vec<_>, _>>()?
-                .into_iter();
-        ))
-    }
-
-    let body = &branch.body;
-    Ok(quote!(
-        _ if #(#conditions &&)* true => {
-            #(#parses)*
-            #body
-        }
-    ))
-}
-
-pub fn match_nodes(
-    input: proc_macro::TokenStream,
-) -> Result<proc_macro2::TokenStream> {
-    let input: MacroInput = syn::parse(input)?;
-
-    let i_nodes = Ident::new("___nodes", input.input_expr.span());
-    let i_node_rules = Ident::new("___node_rules", Span::call_site());
-
-    let input_expr = &input.input_expr;
-    let parser = &input.parser;
-    let branches = input
-        .branches
-        .iter()
-        .map(|br| make_branch(br, &i_nodes, &i_node_rules, parser))
-        .collect::<Result<Vec<_>>>()?;
-
-    Ok(quote!({
-        #[allow(unused_mut)]
-        let mut #i_nodes = #input_expr;
-        let #i_node_rules = #i_nodes.aliased_rules::<#parser>();
-
-        #[allow(unreachable_code)]
-        match () {
-            #(#branches,)*
-            _ => return ::std::result::Result::Err(#i_nodes.error(
-                std::format!("Nodes didn't match any pattern: {:?}", #i_node_rules)
-            )),
-        }
-    }))
-}