ref: a5cb451b299b03f44154fac5780b6a57ca130ce0
dir: /appl/cmd/mash/expr.b/
# # Expression evaluation. # # # Filename pattern matching. # glob(e: ref Env, s: string): (string, list of string) { if (filepat == nil) { filepat = load Filepat Filepat->PATH; if (filepat == nil) e.couldnot("load", Filepat->PATH); } l := filepat->expand(s); if (l != nil) return (nil, l); return (s, nil); } # # RE pattern matching. # match(s1, s2: string): int { (re, nil) := regex->compile(s2, 0); return regex->execute(re, s1) != nil; } # # RE match of two lists. Two non-singleton lists never match. # match2(e: ref Env, s1: string, l1: list of string, s2: string, l2: list of string): int { if (regex == nil) { regex = load Regex Regex->PATH; if (regex == nil) e.couldnot("load", Regex->PATH); } if (s1 != nil) { if (s2 != nil) return match(s1, s2); while (l2 != nil) { if (match(s1, hd l2)) return 1; l2 = tl l2; } } else if (l1 != nil) { if (s2 == nil) return 0; while (l1 != nil) { if (match(hd l1, s2)) return 1; l1 = tl l1; } } else if (s2 != nil) return match(nil, s2); else if (l2 != nil) { while (l2 != nil) { if (match(nil, hd l2)) return 1; l2 = tl l2; } } else return 1; return 0; } # # Test list equality. Same length and identical members. # eqlist(l1, l2: list of string): int { while (l1 != nil && l2 != nil) { if (hd l1 != hd l2) return 0; l1 = tl l1; l2 = tl l2; } return l1 == nil && l2 == nil; } # # Equality operator. # Cmd.evaleq(c: self ref Cmd, e: ref Env): int { (s1, l1, nil) := c.left.eeval2(e); (s2, l2, nil) := c.right.eeval2(e); if (s1 != nil) return s1 == s2; if (l1 != nil) return eqlist(l1, l2); return s2 == nil && l2 == nil; } # # Match operator. # Cmd.evalmatch(c: self ref Cmd, e: ref Env): int { (s1, l1, nil) := c.left.eeval2(e); (s2, l2, nil) := c.right.eeval2(e); return match2(e, s1, l1, s2, l2); } # # Catenation operator. # Item.caret(i: self ref Item, e: ref Env): (string, list of string, int) { (s1, l1, x1) := i.left.ieval2(e); (s2, l2, x2) := i.right.ieval2(e); return caret(s1, l1, x1, s2, l2, x2); } # # Caret of lists. A singleton distributes. Otherwise pairwise, padded with nils. # caret(s1: string, l1: list of string, x1: int, s2: string, l2: list of string, x2: int): (string, list of string, int) { l: list of string; if (s1 != nil) { if (s2 != nil) return (s1 + s2, nil, x1 | x2); if (l2 == nil) return (s1, nil, x1); while (l2 != nil) { l = (s1 + hd l2) :: l; l2 = tl l2; } } else if (s2 != nil) { if (l1 == nil) return (s2, nil, x2); while (l1 != nil) { l = (hd l1 + s2) :: l; l1 = tl l1; } } else if (l1 != nil) { if (l2 == nil) return (nil, l1, 0); while (l1 != nil || l2 != nil) { if (l1 != nil) { s1 = hd l1; l1 = tl l1; } else s1 = nil; if (l2 != nil) { s2 = hd l2; l2 = tl l2; } else s2 = nil; l = (s1 + s2) :: l; } } else if (l2 != nil) return (nil, l2, 0); return (nil, revstrs(l), 0); }