60 lines
1.6 KiB
Go
60 lines
1.6 KiB
Go
// Package strparse provides convenience wrappers around `go/parser` for simple
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// expression, statement and declaration parsing from string.
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//
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// Can be used to construct AST nodes using source syntax.
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package strparse
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import (
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"go/ast"
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"go/parser"
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"go/token"
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)
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var (
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// BadExpr is returned as a parse result for malformed expressions.
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// Should be treated as constant or readonly variable.
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BadExpr = &ast.BadExpr{}
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// BadStmt is returned as a parse result for malformed statmenents.
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// Should be treated as constant or readonly variable.
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BadStmt = &ast.BadStmt{}
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// BadDecl is returned as a parse result for malformed declarations.
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// Should be treated as constant or readonly variable.
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BadDecl = &ast.BadDecl{}
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)
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// Expr parses single expression node from s.
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// In case of parse error, BadExpr is returned.
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func Expr(s string) ast.Expr {
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node, err := parser.ParseExpr(s)
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if err != nil {
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return BadExpr
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}
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return node
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}
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// Stmt parses single statement node from s.
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// In case of parse error, BadStmt is returned.
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func Stmt(s string) ast.Stmt {
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node, err := parser.ParseFile(token.NewFileSet(), "", "package main;func main() {"+s+"}", 0)
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if err != nil {
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return BadStmt
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}
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fn := node.Decls[0].(*ast.FuncDecl)
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if len(fn.Body.List) != 1 {
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return BadStmt
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}
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return fn.Body.List[0]
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}
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// Decl parses single declaration node from s.
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// In case of parse error, BadDecl is returned.
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func Decl(s string) ast.Decl {
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node, err := parser.ParseFile(token.NewFileSet(), "", "package main;"+s, 0)
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if err != nil || len(node.Decls) != 1 {
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return BadDecl
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}
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return node.Decls[0]
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}
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