parse.cpp File Reference

#include "parse.hpp"

Functions
bool	iswhitespace (char ch)
	Check whether the character is whitespace.
bool	is_legalnumeric (string str)
	Check whether numericstr is an legal numericstr string.
bool	is_legaloperator (string str)
	Check whether str is a legal operator.
void	readsinglesymbol (string &substring, string &sexpr)
void	clearwhitespace (string &sexpr)
	Clear the whitespace at the begining and end of string sexpr.
bool	is_legalexpr (string sexpr)
	Check whether the s-expression legal.
Cell *	makecell (string str)
	Make the cell.
Cell *	separate_parse (string &instr)
	Separately parse the sexpr and build the tree.
Cell *	parse (string sexpr)
	Recursively parse sexpr and build the parse tree.

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Detailed Description

Implementation of a parser that analyzes a string containing an s-expression, and determines its tree structure.

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Function Documentation

void clearwhitespace (  string &  sexpr  )

Clear the whitespace at the begining and end of string sexpr. Parameters: sexpr  The string.

bool is_legalexpr (  string  sexpr  )

Check whether the s-expression legal.

bool is_legalnumeric (  string  str  )

Check whether numericstr is an legal numericstr string. Parameters: str  The string to be checked Returns: ture if numericstr is an legal numericstr string, false otherwise

bool is_legaloperator (  string  str  )

Check whether str is a legal operator.

bool iswhitespace (  char  ch  )

Check whether the character is whitespace. Returns: True if it is character, false else. Parameters: ch  The character to check.

Cell* makecell (  string  str  )

Make the cell. Parameters: str  The string to represent the symbol, int or double.

Cell* parse (  string  sexpr  )

Recursively parse sexpr and build the parse tree. Parameters: sexpr  The s-expression stored in a string variable (note that this version of parse has side effects: it may alter the contents of sexpr). Returns: A pointer to the conspair cell at the root of the parse tree.

void readsinglesymbol (  string &  substring, string &  sexpr )

Cell * separate_parse (  string &  instr  )

Separately parse the sexpr and build the tree. Parameters: instr  The string which consists of s-expressions. Returns: A pointer to the conspair cell at the root of the parse tree.

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