From 9219068a8680d3b7fc8c89bd14f81b094423f5a2 Mon Sep 17 00:00:00 2001
From: Tan Kian-ting <chenjt30@gmail.com>
Date: Tue, 5 Aug 2025 21:55:40 +0800
Subject: [PATCH] add combinator

---
 src/parser.jl | 83 +++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 80 insertions(+), 3 deletions(-)

diff --git a/src/parser.jl b/src/parser.jl
index 537585a..7578b31 100644
--- a/src/parser.jl
+++ b/src/parser.jl
@@ -1,5 +1,77 @@
 module Parser
 
+struct ParserResult
+    matched
+    remained
+end
+
+OptParserResult = Union{Nothing,ParserResult}
+
+struct Psr
+    fun
+end
+
+function strng(c)
+    return Psr((x)-> length(x) >= 1 ?
+        (x[1][1] == c ?
+            ParserResult([x[1]], x[2:end])
+            : nothing)
+        : nothing)
+end
+
+function type(t)
+    return Psr((x)-> length(x) >= 1 ?
+        (x[1][2] == t ?
+            ParserResult([x[1]], x[2:end])
+            : nothing)
+        : nothing)
+end
+
+(>>)(a::OptParserResult, b::Psr) = then(a, b)
+
+function then(a, b)
+    if a == nothing
+        return a
+    else
+        return b.fun(a.remained)
+    end
+end
+
+(|)(a::Psr, b::Psr) = choice(a, b)
+
+function choice(a, b)
+    return Psr((x)-> (a.fun(x) == nothing ? b.fun(x) : a.fun(x)))
+end
+
+
+
+function seq(parserLst)
+    function seqAux(s)
+        result  = []
+        isNothing = false
+        tmp = nothing
+
+        for p in parserLst
+            println("s+=+=", s)
+            tmp = p.fun(s)
+            println("tmp%%%%", tmp)
+            if tmp == nothing
+                return nothing
+            else
+                s = tmp.remained)
+                push!(result, tmp.matched)
+                
+            end
+        end
+
+        return ParserResult(result, s)
+    end
+
+    return Psr(seqAux)
+end
+
+
+
 patternList = [("int", "\\d+"),
                ("id", "[_a-zA-Z][_0-9a-zA-Z]*"),
                ("l_paren", "[\\(]"),
@@ -53,12 +125,17 @@ matchedList = map((x)->x.match, collect(mI))
 
 groupNameList = map(processKeys, collect(mI))
 
-list1 = [1, 2, 3]
-list2 = ["a", "b", "c"]
-
 zippedTokenList = collect(zip(matchedList, groupNameList))
 
 print(zippedTokenList)
 
+withoutSpaces = filter((x)-> x[2] != "sp", zippedTokenList)
+initWrapped = ParserResult([], withoutSpaces)
+
+
+println(initWrapped >> strng("123") >> (strng("+")|strng("-")))
+println(initWrapped >> seq([strng("123"),  strng("+")]))
+
+
 end