Macintosh-SW/mpw-shell
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add regular expression support for evaluate, if, etc.

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eg:

evaluate abc =~ /(abc)®4/ # sets the '@4' environment variable.
evaluate abc !~ /[aA]bc/

MPW regular expressions are converted to c++11 std::regex regular expressions and evaluated.
Sadly, the // regular expression syntax interferes with unix-paths (if the / count is odd).  quoting or ∂-escaping the /s is therefore necessary.

file globbing is not yet implemented.
This commit is contained in:
Kelvin Sherlock
2022-11-22 17:22:49 -05:00
parent a90ca3c849
commit ce1a36eba5
12 changed files with 431 additions and 20 deletions
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40
mpw-shell-parser.cpp
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@@ -2,6 +2,7 @@
#include "fdset.h"
#include "value.h"
#include "error.h"
#include "mpw-regex.h"
#include <unistd.h>
#include <fcntl.h>
@@ -172,8 +173,8 @@ class expression_parser {
public:
expression_parser(const std::string &n, std::vector<token> &&t) :
name(n), tokens(std::move(t))
expression_parser(Environment &e, const std::string &n, std::vector<token> &&t) :
environment(e), name(n), tokens(std::move(t))
{}
expression_parser(const expression_parser &) = delete;
@@ -194,6 +195,7 @@ private:
value eval(int op, value &lhs, value &rhs);
value eval_regex(value &lhs, value &rhs);
[[noreturn]] void expect_binary_operator();
[[noreturn]] void end_of_expression();
@@ -207,6 +209,7 @@ private:
if (!tokens.empty()) tokens.pop_back();
}
Environment &environment;
const std::string &name;
std::vector<token> tokens;
};
@@ -323,8 +326,8 @@ int expression_parser::precedence(int op) {
case '==':
case '!=':
case token::equivalent:
case token::not_equivalent:
case '=~':
case '!~':
return 7;
case '&':
return 8;
@@ -341,6 +344,25 @@ int expression_parser::precedence(int op) {
//throw std::runtime_error("unimplemented op";);
}
value expression_parser::eval_regex(value &lhs, value &rhs) {
try {
mpw_regex re(rhs.string, true);
// todo -- need environment to store matches.
bool ok = re.match(lhs.string, environment);
return ok ? 1 : 0;
} catch (std::exception &ex) {
std::string error;
error = name;
if (rhs.string.empty() || rhs.string.front() != '/')
error += " - Missing /s around regular expression: ";
else
error += " - Invalid regular expression encountered: ";
error += rhs.string;
throw mpw_error(-5, error);
}
}
value expression_parser::eval(int op, value &lhs, value &rhs) {
switch (op) {
@@ -407,6 +429,12 @@ value expression_parser::eval(int op, value &lhs, value &rhs) {
return lhs.string != rhs.string;
case '=~':
return eval_regex(lhs, rhs);
case '!~':
return !eval_regex(lhs, rhs).number;
}
// todo...
throw std::runtime_error("unimplemented op");
@@ -469,8 +497,8 @@ int32_t expression_parser::evaluate() {
return v.to_number(1);
}
int32_t evaluate_expression(const std::string &name, std::vector<token> &&tokens) {
int32_t evaluate_expression(Environment &env, const std::string &name, std::vector<token> &&tokens) {
expression_parser p(name, std::move(tokens));
expression_parser p(env, name, std::move(tokens));
return p.evaluate();
}