From a86088505de38c9b3d4c4bb8feecab28055514d8 Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Tue, 10 Sep 2019 13:57:43 +0200 Subject: Rename parse_children to match_inputs --- pest_consume_macros/src/lib.rs | 6 +- pest_consume_macros/src/match_inputs.rs | 206 ++++++++++++++++++++++++++++++ pest_consume_macros/src/parse_children.rs | 206 ------------------------------ 3 files changed, 209 insertions(+), 209 deletions(-) create mode 100644 pest_consume_macros/src/match_inputs.rs delete mode 100644 pest_consume_macros/src/parse_children.rs (limited to 'pest_consume_macros') diff --git a/pest_consume_macros/src/lib.rs b/pest_consume_macros/src/lib.rs index dd437f6..b5368ec 100644 --- a/pest_consume_macros/src/lib.rs +++ b/pest_consume_macros/src/lib.rs @@ -7,7 +7,7 @@ extern crate proc_macro; mod make_parser; -mod parse_children; +mod match_inputs; use proc_macro::TokenStream; @@ -20,8 +20,8 @@ pub fn make_parser(attrs: TokenStream, input: TokenStream) -> TokenStream { } #[proc_macro] -pub fn parse_children(input: TokenStream) -> TokenStream { - TokenStream::from(match parse_children::parse_children(input) { +pub fn match_inputs(input: TokenStream) -> TokenStream { + TokenStream::from(match match_inputs::match_inputs(input) { Ok(tokens) => tokens, Err(err) => err.to_compile_error(), }) diff --git a/pest_consume_macros/src/match_inputs.rs b/pest_consume_macros/src/match_inputs.rs new file mode 100644 index 0000000..3a325a6 --- /dev/null +++ b/pest_consume_macros/src/match_inputs.rs @@ -0,0 +1,206 @@ +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, token, Error, Expr, Ident, Pat, Token}; + +#[derive(Debug, Clone)] +struct ChildrenBranch { + pattern_span: Span, + pattern: Punctuated, + body: Expr, +} + +#[derive(Debug, Clone)] +enum ChildrenBranchPatternItem { + Single { rule_name: Ident, binder: Pat }, + Multiple { rule_name: Ident, binder: Ident }, +} + +#[derive(Debug, Clone)] +struct ParseChildrenInput { + input_expr: Expr, + branches: Punctuated, +} + +impl Parse for ChildrenBranch { + fn parse(input: ParseStream) -> Result { + let contents; + let _: token::Bracket = bracketed!(contents in input); + let pattern_unparsed: TokenStream = contents.fork().parse()?; + let pattern_span = pattern_unparsed.span(); + let pattern = Punctuated::parse_terminated(&contents)?; + let _: Token![=>] = input.parse()?; + let body = input.parse()?; + + Ok(ChildrenBranch { + pattern_span, + pattern, + body, + }) + } +} + +impl Parse for ChildrenBranchPatternItem { + fn parse(input: ParseStream) -> Result { + let contents; + let rule_name = input.parse()?; + parenthesized!(contents in input); + if input.peek(Token![..]) { + let binder = contents.parse()?; + let _: Token![..] = input.parse()?; + Ok(ChildrenBranchPatternItem::Multiple { rule_name, binder }) + } else if input.is_empty() || input.peek(Token![,]) { + let binder = contents.parse()?; + Ok(ChildrenBranchPatternItem::Single { rule_name, binder }) + } else { + Err(input.error("expected `..` or nothing")) + } + } +} + +impl Parse for ParseChildrenInput { + fn parse(input: ParseStream) -> Result { + let input_expr = input.parse()?; + let _: Token![;] = input.parse()?; + let branches = Punctuated::parse_terminated(input)?; + + Ok(ParseChildrenInput { + input_expr, + branches, + }) + } +} + +fn make_parser_branch( + branch: &ChildrenBranch, + i_inputs: &Ident, +) -> Result { + use ChildrenBranchPatternItem::{Multiple, Single}; + + let body = &branch.body; + + // Convert the input pattern into a pattern-match on the Rules of the children. This uses + // slice_patterns. + // A single pattern just checks that the rule matches; a variable-length pattern binds the + // subslice and checks, in the if-guard, that its elements all match the chosen Rule. + let i_variable_pattern = + Ident::new("___variable_pattern", Span::call_site()); + let match_pat = branch.pattern.iter().map(|item| match item { + Single { rule_name, .. } => quote!(stringify!(#rule_name)), + Multiple { .. } => quote!(#i_variable_pattern @ ..), + }); + let match_filter = branch.pattern.iter().map(|item| match item { + Single { .. } => quote!(), + Multiple { rule_name, .. } => 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 == stringify!(#rule_name) + ) + }; + all_match(#i_variable_pattern) + } && + ), + }); + + // Once we have found a branch that matches, we need to parse the children. + let mut singles_before_multiple = Vec::new(); + let mut multiple = None; + let mut singles_after_multiple = Vec::new(); + for item in &branch.pattern { + 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, .. + } => { + if multiple.is_none() { + multiple = Some((rule_name, binder)) + } else { + return Err(Error::new( + branch.pattern_span.clone(), + "multiple variable-length patterns are not allowed", + )); + } + } + } + } + let mut parses = Vec::new(); + for (rule_name, binder) in singles_before_multiple.into_iter() { + parses.push(quote!( + let #binder = Self::#rule_name( + #i_inputs.next().unwrap() + )?; + )) + } + // Note the `rev()`: we are taking inputs from the end of the iterator in reverse order, so that + // only the unmatched inputs are left for the variable-length pattern, if any. + for (rule_name, binder) in singles_after_multiple.into_iter().rev() { + parses.push(quote!( + let #binder = Self::#rule_name( + #i_inputs.next_back().unwrap() + )?; + )) + } + if let Some((rule_name, binder)) = multiple { + parses.push(quote!( + let #binder = #i_inputs + .map(|i| Self::#rule_name(i)) + .collect::, _>>()? + .into_iter(); + )) + } + + Ok(quote!( + [#(#match_pat),*] if #(#match_filter)* true => { + #(#parses)* + #body + } + )) +} + +pub fn match_inputs( + input: proc_macro::TokenStream, +) -> Result { + let input: ParseChildrenInput = syn::parse(input)?; + + let i_input_rules = Ident::new("___input_rules", Span::call_site()); + let i_inputs = Ident::new("___inputs", Span::call_site()); + + let input_expr = &input.input_expr; + let branches = input + .branches + .iter() + .map(|br| make_parser_branch(br, &i_inputs)) + .collect::>>()?; + + Ok(quote!({ + #[allow(unused_mut)] + let mut #i_inputs = #input_expr; + + let #i_input_rules = #i_inputs.aliased_rules::(); + let #i_input_rules: Vec<&str> = #i_input_rules + .iter() + .map(String::as_str) + .collect(); + + #[allow(unreachable_code)] + match #i_input_rules.as_slice() { + #(#branches,)* + [..] => return Err(#i_inputs.error( + format!("Unexpected children: {:?}", #i_input_rules) + )), + } + })) +} diff --git a/pest_consume_macros/src/parse_children.rs b/pest_consume_macros/src/parse_children.rs deleted file mode 100644 index 8feef03..0000000 --- a/pest_consume_macros/src/parse_children.rs +++ /dev/null @@ -1,206 +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, token, Error, Expr, Ident, Pat, Token}; - -#[derive(Debug, Clone)] -struct ChildrenBranch { - pattern_span: Span, - pattern: Punctuated, - body: Expr, -} - -#[derive(Debug, Clone)] -enum ChildrenBranchPatternItem { - Single { rule_name: Ident, binder: Pat }, - Multiple { rule_name: Ident, binder: Ident }, -} - -#[derive(Debug, Clone)] -struct ParseChildrenInput { - input_expr: Expr, - branches: Punctuated, -} - -impl Parse for ChildrenBranch { - fn parse(input: ParseStream) -> Result { - let contents; - let _: token::Bracket = bracketed!(contents in input); - let pattern_unparsed: TokenStream = contents.fork().parse()?; - let pattern_span = pattern_unparsed.span(); - let pattern = Punctuated::parse_terminated(&contents)?; - let _: Token![=>] = input.parse()?; - let body = input.parse()?; - - Ok(ChildrenBranch { - pattern_span, - pattern, - body, - }) - } -} - -impl Parse for ChildrenBranchPatternItem { - fn parse(input: ParseStream) -> Result { - let contents; - let rule_name = input.parse()?; - parenthesized!(contents in input); - if input.peek(Token![..]) { - let binder = contents.parse()?; - let _: Token![..] = input.parse()?; - Ok(ChildrenBranchPatternItem::Multiple { rule_name, binder }) - } else if input.is_empty() || input.peek(Token![,]) { - let binder = contents.parse()?; - Ok(ChildrenBranchPatternItem::Single { rule_name, binder }) - } else { - Err(input.error("expected `..` or nothing")) - } - } -} - -impl Parse for ParseChildrenInput { - fn parse(input: ParseStream) -> Result { - let input_expr = input.parse()?; - let _: Token![;] = input.parse()?; - let branches = Punctuated::parse_terminated(input)?; - - Ok(ParseChildrenInput { - input_expr, - branches, - }) - } -} - -fn make_parser_branch( - branch: &ChildrenBranch, - i_inputs: &Ident, -) -> Result { - use ChildrenBranchPatternItem::{Multiple, Single}; - - let body = &branch.body; - - // Convert the input pattern into a pattern-match on the Rules of the children. This uses - // slice_patterns. - // A single pattern just checks that the rule matches; a variable-length pattern binds the - // subslice and checks, in the if-guard, that its elements all match the chosen Rule. - let i_variable_pattern = - Ident::new("___variable_pattern", Span::call_site()); - let match_pat = branch.pattern.iter().map(|item| match item { - Single { rule_name, .. } => quote!(stringify!(#rule_name)), - Multiple { .. } => quote!(#i_variable_pattern @ ..), - }); - let match_filter = branch.pattern.iter().map(|item| match item { - Single { .. } => quote!(), - Multiple { rule_name, .. } => 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 == stringify!(#rule_name) - ) - }; - all_match(#i_variable_pattern) - } && - ), - }); - - // Once we have found a branch that matches, we need to parse the children. - let mut singles_before_multiple = Vec::new(); - let mut multiple = None; - let mut singles_after_multiple = Vec::new(); - for item in &branch.pattern { - 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, .. - } => { - if multiple.is_none() { - multiple = Some((rule_name, binder)) - } else { - return Err(Error::new( - branch.pattern_span.clone(), - "multiple variable-length patterns are not allowed", - )); - } - } - } - } - let mut parses = Vec::new(); - for (rule_name, binder) in singles_before_multiple.into_iter() { - parses.push(quote!( - let #binder = Self::#rule_name( - #i_inputs.next().unwrap() - )?; - )) - } - // Note the `rev()`: we are taking inputs from the end of the iterator in reverse order, so that - // only the unmatched inputs are left for the variable-length pattern, if any. - for (rule_name, binder) in singles_after_multiple.into_iter().rev() { - parses.push(quote!( - let #binder = Self::#rule_name( - #i_inputs.next_back().unwrap() - )?; - )) - } - if let Some((rule_name, binder)) = multiple { - parses.push(quote!( - let #binder = #i_inputs - .map(|i| Self::#rule_name(i)) - .collect::, _>>()? - .into_iter(); - )) - } - - Ok(quote!( - [#(#match_pat),*] if #(#match_filter)* true => { - #(#parses)* - #body - } - )) -} - -pub fn parse_children( - input: proc_macro::TokenStream, -) -> Result { - let input: ParseChildrenInput = syn::parse(input)?; - - let i_input_rules = Ident::new("___input_rules", Span::call_site()); - let i_inputs = Ident::new("___inputs", Span::call_site()); - - let input_expr = &input.input_expr; - let branches = input - .branches - .iter() - .map(|br| make_parser_branch(br, &i_inputs)) - .collect::>>()?; - - Ok(quote!({ - #[allow(unused_mut)] - let mut #i_inputs = #input_expr; - - let #i_input_rules = #i_inputs.aliased_rules::(); - let #i_input_rules: Vec<&str> = #i_input_rules - .iter() - .map(String::as_str) - .collect(); - - #[allow(unreachable_code)] - match #i_input_rules.as_slice() { - #(#branches,)* - [..] => return Err(#i_inputs.error( - format!("Unexpected children: {:?}", #i_input_rules) - )), - } - })) -} -- cgit v1.2.3