Move extfmt parsing into standard library

1 files changed, 213 insertions, 0 deletions

diff --git a/src/lib/ExtFmt.rs b/src/lib/ExtFmt.rs
index 15f7ff83..f7487eec 100644
--- a/src/lib/ExtFmt.rs
+++ b/src/lib/ExtFmt.rs
@@ -1,3 +1,6 @@
+import option.none;
+import option.some;
+
 tag signedness {
     signed;
     unsigned;
@@ -45,3 +48,213 @@ tag piece {
     piece_string(str);
     piece_conv(conv);
 }
+
+fn parse_fmt_string(str s) -> vec[piece] {
+    let vec[piece] pieces = vec();
+    auto lim = _str.byte_len(s);
+    auto buf = "";
+
+    fn flush_buf(str buf, &vec[piece] pieces) -> str {
+        if (_str.byte_len(buf) > 0u) {
+            auto piece = piece_string(buf);
+            pieces += vec(piece);
+        }
+        ret "";
+    }
+
+    auto i = 0u;
+    while (i < lim) {
+        auto curr = _str.substr(s, i, 1u);
+        if (_str.eq(curr, "%")) {
+            i += 1u;
+            if (i >= lim) {
+                log "unterminated conversion at end of string";
+                fail;
+            }
+            auto curr2 = _str.substr(s, i, 1u);
+            if (_str.eq(curr2, "%")) {
+                i += 1u;
+            } else {
+                buf = flush_buf(buf, pieces);
+                auto res = parse_conversion(s, i, lim);
+                pieces += vec(res._0);
+                i = res._1;
+            }
+        } else {
+            buf += curr;
+            i += 1u;
+        }
+    }
+    buf = flush_buf(buf, pieces);
+    ret pieces;
+}
+
+fn peek_num(str s, uint i, uint lim) -> option.t[tup(uint, uint)] {
+    if (i >= lim) {
+        ret none[tup(uint, uint)];
+    }
+
+    auto c = s.(i);
+    if (!('0' as u8 <= c && c <= '9' as u8)) {
+        ret option.none[tup(uint, uint)];
+    }
+
+    auto n = (c - ('0' as u8)) as uint;
+    alt (peek_num(s, i + 1u, lim)) {
+        case (none[tup(uint, uint)]) {
+            ret some[tup(uint, uint)](tup(n, i + 1u));
+        }
+        case (some[tup(uint, uint)](?next)) {
+            auto m = next._0;
+            auto j = next._1;
+            ret some[tup(uint, uint)](tup(n * 10u + m, j));
+        }
+    }
+
+}
+
+fn parse_conversion(str s, uint i, uint lim) -> tup(piece, uint) {
+    auto parm = parse_parameter(s, i, lim);
+    auto flags = parse_flags(s, parm._1, lim);
+    auto width = parse_count(s, flags._1, lim);
+    auto prec = parse_precision(s, width._1, lim);
+    auto ty = parse_type(s, prec._1, lim);
+    ret tup(piece_conv(rec(param = parm._0,
+                           flags = flags._0,
+                           width = width._0,
+                           precision = prec._0,
+                           ty = ty._0)),
+            ty._1);
+}
+
+fn parse_parameter(str s, uint i, uint lim) -> tup(option.t[int], uint) {
+    if (i >= lim) {
+        ret tup(none[int], i);
+    }
+
+    auto num = peek_num(s, i, lim);
+    alt (num) {
+        case (none[tup(uint, uint)]) {
+            ret tup(none[int], i);
+        }
+        case (some[tup(uint, uint)](?t)) {
+            auto n = t._0;
+            auto j = t._1;
+            if (j < lim && s.(j) == '$' as u8) {
+                ret tup(some[int](n as int), j + 1u);
+            }
+            else {
+                ret tup(none[int], i);
+            }
+        }
+    }
+}
+
+fn parse_flags(str s, uint i, uint lim) -> tup(vec[flag], uint) {
+    let vec[flag] noflags = vec();
+
+    if (i >= lim) {
+        ret tup(noflags, i);
+    }
+
+    fn more_(flag f, str s, uint i, uint lim) -> tup(vec[flag], uint) {
+        auto next = parse_flags(s, i + 1u, lim);
+        auto rest = next._0;
+        auto j = next._1;
+        let vec[flag] curr = vec(f);
+        ret tup(curr + rest, j);
+    }
+
+    auto more = bind more_(_, s, i, lim);
+
+    auto f = s.(i);
+    if (f == ('-' as u8)) {
+        ret more(flag_left_justify);
+    } else if (f == ('0' as u8)) {
+        ret more(flag_left_zero_pad);
+    } else if (f == (' ' as u8)) {
+        ret more(flag_left_space_pad);
+    } else if (f == ('+' as u8)) {
+        ret more(flag_plus_if_positive);
+    } else if (f == ('#' as u8)) {
+        ret more(flag_alternate);
+    } else {
+        ret tup(noflags, i);
+    }
+}
+
+fn parse_count(str s, uint i, uint lim) -> tup(count, uint) {
+    if (i >= lim) {
+        ret tup(count_implied, i);
+    }
+
+    if (s.(i) == ('*' as u8)) {
+        auto param = parse_parameter(s, i + 1u, lim);
+        auto j = param._1;
+        alt (param._0) {
+            case (none[int]) {
+                ret tup(count_is_next_param, j);
+            }
+            case (some[int](?n)) {
+                ret tup(count_is_param(n), j);
+            }
+        }
+    } else {
+        auto num = peek_num(s, i, lim);
+        alt (num) {
+            case (none[tup(uint, uint)]) {
+                ret tup(count_implied, i);
+            }
+            case (some[tup(uint, uint)](?num)) {
+                ret tup(count_is(num._0 as int), num._1);
+            }
+        }
+    }
+}
+
+fn parse_precision(str s, uint i, uint lim) -> tup(count, uint) {
+    if (i >= lim) {
+        ret tup(count_implied, i);
+    }
+
+    if (s.(i) == '.' as u8) {
+        ret parse_count(s, i + 1u, lim);
+    } else {
+        ret tup(count_implied, i);
+    }
+}
+
+fn parse_type(str s, uint i, uint lim) -> tup(ty, uint) {
+    if (i >= lim) {
+        log "missing type in conversion";
+        fail;
+    }
+
+    auto t;
+    auto tstr = _str.substr(s, i, 1u);
+    if (_str.eq(tstr, "b")) {
+        t = ty_bool;
+    } else if (_str.eq(tstr, "s")) {
+        t = ty_str;
+    } else if (_str.eq(tstr, "c")) {
+        t = ty_char;
+    } else if (_str.eq(tstr, "d")
+               || _str.eq(tstr, "i")) {
+        // TODO: Do we really want two signed types here?
+        // How important is it to be printf compatible?
+        t = ty_int(signed);
+    } else if (_str.eq(tstr, "u")) {
+        t = ty_int(unsigned);
+    } else if (_str.eq(tstr, "x")) {
+        t = ty_hex(case_lower);
+    } else if (_str.eq(tstr, "X")) {
+        t = ty_hex(case_upper);
+    } else if (_str.eq(tstr, "t")) {
+        t = ty_bits;
+    } else {
+        log "unknown type in conversion";
+        fail;
+    }
+
+    ret tup(t, i + 1u);
+}